Web Hosting Glossary

A Record

Address Record

The DNS record that points a domain or subdomain straight at an IPv4 address. This is usually the first thing you edit when moving hosts.

AAAA Record

IPv6 Address Record

Does the same job as an A record, just for IPv6 addresses instead of IPv4.

ACL

Access Control List

A set of rules defining exactly who — or which IP addresses — can access a specific resource, and what they're allowed to do once they're in.

Addon Domain

Additional Hosted Domain

A separate, fully functional domain hosted within the same cPanel account as your primary domain, without needing a new hosting plan.

AI

Artificial Intelligence

The broad umbrella term for software that performs tasks — writing, recognizing images, holding a conversation — that would normally require human judgment.

AI Website Builder

Automated Site Generator

A tool that generates a starting layout, images, and copy for a website based on a short description you give it, cutting out a lot of the blank-page setup work.

Anycast

Routing Technique

Lets the same IP address be announced from multiple locations at once, so traffic automatically routes to whichever is closest or healthiest.

API

Application Programming Interface

A defined set of rules that lets two pieces of software talk to each other, without either one needing to know how the other works internally.

API Key

Access Credential

A unique code that authenticates your requests to an AI (or other) service, tracks your usage, and keeps your account separate from everyone else's.

AUP

Acceptable Use Policy

The rules governing what you can and can't run on a hosting account — things like resource limits, prohibited content, and acceptable email sending practices.

Auto-Renewal

Automatic Billing

Automatically charges your saved payment method and renews a domain or hosting plan before it expires, so you don't lose it to a missed deadline.

Backlink

Inbound Link

A link from another website pointing to yours. Search engines generally treat backlinks — especially from reputable sites — as a vote of confidence in your content.

Backup / Snapshot

Data Recovery Point

A backup copies your files and databases; a snapshot captures the entire server state at a point in time so you can roll back if something breaks.

Bandwidth

Data Transfer Capacity

How much data can move to and from your server in a given period — usually the thing that gets throttled first if a site suddenly goes viral.

Bare Metal Server

Non-Virtualized Hardware

Essentially another name for a dedicated server, used to emphasize that there's no virtualization layer at all sitting between you and the physical hardware.

Blocklist / Blacklist

Reputation Database

A list of IP addresses or domains flagged as spam sources. Getting listed on one can quietly tank your email deliverability until you're removed.

Bounce (Hard / Soft)

Delivery Failure

A hard bounce means the email failed permanently, usually a bad address; a soft bounce means it failed temporarily — a full inbox, a server hiccup — and may still go through on retry.

Brute Force Attack

Credential Guessing Attack

An attacker (or a bot) rapidly tries huge numbers of password combinations against a login form, hoping one eventually works.

CAA Record

Certification Authority Authorization

Specifies which certificate authorities are allowed to issue SSL certificates for your domain, blocking anyone else from issuing one without your knowledge.

Cache

Temporary Data Storage

A stored copy of something (a page, a database query, an image) kept ready to serve instantly, so the server doesn't have to rebuild it from scratch on every single visit.

Cache Purge

Cache Clearing Action

Manually clears cached versions of your pages so visitors immediately see the latest content instead of an outdated cached copy.

CAPTCHA

Human Verification Challenge

Those "prove you're not a robot" checks on forms, designed to block automated bots without slowing down real users too much.

Catch-all Email

Fallback Address

A mailbox that receives anything sent to your domain with no matching address, so nothing addressed to a typo'd or old inbox gets lost.

CDN

Content Delivery Network

A network of servers spread across different locations that cache your site's content closer to visitors, cutting load times. Many hosts bundle a free tier, most commonly through Cloudflare.

Chatbot

Conversational Interface

A program that simulates a text (or voice) conversation, ranging from simple scripted responses to full AI-driven assistants that can handle open-ended questions.

Child Theme

Theme Customization Layer

A theme that inherits everything from a "parent" theme, letting you customize the design safely without your changes being wiped out the next time the parent theme updates.

Chroot Jail

Restricted Filesystem Environment

Confines a process (or user) to a specific directory tree, so it can't see or touch files outside that sandbox even if compromised.

CI / CD

Continuous Integration / Continuous Deployment

The practice of automatically testing and shipping code changes, instead of manually building and uploading every update by hand.

Cloud Hosting

Distributed Infrastructure

Rather than running on a single physical server, your site draws resources from a connected pool of machines, so it can typically absorb traffic spikes or hardware hiccups more gracefully.

CloudLinux

Shared Hosting OS

A Linux distribution built specifically for shared hosting environments, designed to isolate accounts from one another so a problem on one site doesn't spill over onto its neighbors.

CMS

Content Management System

Software like WordPress or Joomla that lets you build and update a website without writing raw HTML for every page.

CNAME

Canonical Name Record

Points one domain or subdomain to another domain name rather than to an IP address directly — common for things like www pointing to the root domain.

Colocation Hosting

Self-Owned Hardware, Rented Space

You own the physical server, but it lives in the provider's data center, using their power, cooling, and network connection instead of yours.

Console

Direct Access Terminal

A browser-based terminal built into your hosting dashboard for VPS and VDS servers, giving you a way in even if SSH is unreachable — say, after a firewall misconfiguration locks out normal remote access.

Conversion Rate

Goal Completion Percentage

The share of visitors who complete whatever action you actually want — a purchase, a signup, a form submission — out of everyone who showed up.

Core Web Vitals

Page Experience Metrics

A specific set of speed and stability measurements Google uses to judge how a page feels to use, and one of the factors that can influence search rankings.

cPanel / WHM

Control Panel / Web Host Manager

cPanel is the dashboard most hosting customers use to manage domains, email, and files. WHM is the admin-level panel hosts and resellers use to manage cPanel accounts underneath it.

Cron / CRON

Scheduled Task Daemon

Runs commands or scripts automatically on a schedule you set. Despite what a lot of people assume, it's not really an acronym — the name most likely traces back to the Greek word for time, "chronos."

CSR

Certificate Signing Request

A block of encoded text you generate on your server and submit to a certificate authority to request an SSL certificate.

cURL

Client URL

A command-line tool for sending HTTP requests directly from a terminal — extremely common in setup guides and API testing.

Data Center

Physical Server Facility

The building where your server's actual hardware lives, with staff, power redundancy, cooling, and network connectivity managed around the clock rather than left to chance.

Data Center Tier (I–IV)

Reliability Classification

A rating system for how redundant a data center's power and cooling infrastructure is. Tier IV facilities can lose a component without any downtime; Tier I can't.

DCV

Domain Control Validation

The check a certificate authority runs to confirm you actually control a domain before issuing an SSL certificate for it.

DDoS

Distributed Denial of Service

An attack that floods a server with traffic from many sources at once, trying to overwhelm it so real visitors can't get through.

Dedicated Server

Single-Tenant Hardware

An entire physical machine reserved for one customer. Maximum performance and control, but you're also responsible for more of the upkeep.

Disk Quota

Storage Allocation Limit

The maximum amount of storage your hosting plan allows for files, databases, and email combined.

DKIM

DomainKeys Identified Mail

Attaches a cryptographic signature to outgoing email so the receiving server can confirm the message wasn't altered in transit.

DMARC

Domain-based Message Authentication, Reporting & Conformance

Builds on SPF and DKIM by telling receiving servers what to do with mail that fails those checks — and can send you reports on spoofing attempts.

DNS

Domain Name System

The internet's phonebook — it translates a domain name like yoursite.com into the IP address computers actually use to find it.

DNS Propagation

Record Update Delay

The window of time it takes for a DNS change to update across every resolver on the internet — usually minutes, but it can stretch to 24–48 hours.

DNS Zone Editor

Record Management Tool

The interface in your control panel for adding, editing, or removing individual DNS records like A, CNAME, and MX, without needing to touch a raw zone file.

Docker

Containerization Platform

Packages an app with everything it needs to run into a single portable container, so it behaves the same on your laptop as it does in production.

Domain Forwarding

URL Redirect

Sends visitors from one domain to a different URL entirely — unlike a parked domain, which shows the same content while keeping the original address in the browser bar.

Domain Lock / Transfer Lock

Transfer Protection

A setting that blocks a domain from being moved to another registrar without your say-so, mainly there to stop unauthorized transfers.

Domain Registrar

Domain Sales Provider

The accredited company you actually buy and renew a domain name through, separate from whoever hosts the site living on that domain.

Email Alias

Forwarding Address

An extra email address that forwards to an existing mailbox, letting you use several addresses — like sales@ and info@ — without managing a separate inbox for each one.

Email Marketing

Direct Audience Outreach

Sending newsletters, promotions, or updates straight to a list of subscribers, generally through dedicated software rather than a regular inbox.

Embedding

Vector Representation

A numeric representation of text (or images) that captures meaning, letting a system compare how similar two pieces of content are mathematically.

.env

Environment Variables File

Keeps sensitive values like API keys and database passwords out of your codebase, so they're not sitting in version control for anyone to find.

EPP Code

Authorization / Transfer Code

A unique code your current registrar gives you to prove ownership when transferring a domain to a new registrar.

ERR_CONNECTION_TIMED_OUT

Browser Connection Error

The browser couldn't establish a connection to the server at all — this points to a network or DNS issue rather than anything wrong with the website's code itself.

Fail2ban

Intrusion Prevention Tool

Watches your server logs for repeated failed login attempts and automatically bans the offending IP addresses for a set period.

File Manager

Browser-Based File Tool

A cPanel feature for uploading, editing, and organizing your site's files right in the browser — no FTP client required.

Firewall

Traffic Filtering System

The broader category UFW and WAF both belong to — software or hardware that decides which network traffic is allowed to reach a server and which gets blocked.

FQDN

Fully Qualified Domain Name

A domain name written out in full, including the host and top-level domain — e.g., server1.example.com rather than just "server1."

Free Domain

Bundled Registration

A domain name included at no extra cost with certain hosting plans, typically for the first year, after which it renews at the standard registration price.

FTP

File Transfer Protocol

An older method for moving files to and from a server. Still around, but it sends data unencrypted, so it's fading out in favor of SFTP.

FTP Client

Local File Transfer App

The program you install on your own computer to actually connect to your server over FTP or SFTP. FileZilla is the most common free option, with Cyberduck and WinSCP as popular alternatives.

Generative AI

Content-Creating AI

AI systems that produce new content — text, images, code — rather than just analyzing or classifying existing content.

Git

Version Control System

Tracks changes to code over time, letting multiple people work on the same project without overwriting each other's changes.

GPU

Graphics Processing Unit

A chip originally built for rendering graphics that turns out to be extremely good at the math behind AI, which is why "GPU hosting" has become its own category for running AI workloads.

Grace Period

Renewal Buffer

A short window after a hosting or domain plan expires where service keeps running before it's actually suspended or the domain is released for anyone else to register.

Greylisting

Anti-Spam Technique

Temporarily rejects mail from unfamiliar senders; legitimate servers retry automatically, while a lot of spam sources never bother.

Gzip / Brotli Compression

File Compression

Shrinks files before sending them to a visitor's browser, which then unpacks them on arrival — cutting load times without changing what's actually on the page.

Hallucination

Fabricated AI Output

When an AI model confidently states something false or made-up as though it were fact, usually because it's predicting plausible-sounding text rather than looking anything up.

HSTS

HTTP Strict Transport Security

A setting that tells browsers to only ever connect to your site over HTTPS, refusing plain HTTP even if someone types it in directly.

.htaccess

Apache Configuration File

A per-directory config file used for redirects, custom error pages, and access rules — one of the most commonly edited (and broken) files in shared hosting.

HTTP

HyperText Transfer Protocol

The underlying protocol browsers and servers use to request and send web pages.

HTTP/2 / HTTP/3

Modern HTTP Versions

Newer revisions of the HTTP protocol that load multiple resources over a single connection more efficiently, cutting page load times compared to HTTP/1.1.

HTTPS

HTTP Secure

HTTP wrapped in SSL/TLS encryption, so data moving between browser and server can't be read or tampered with in transit.

IDN

Internationalized Domain Name

A domain name that includes non-ASCII characters, like accented letters or non-Latin scripts, converted behind the scenes into a format browsers can read.

IMAP

Internet Message Access Protocol

Keeps email synced on the server so you can check the same inbox from your phone, laptop, and webmail without messages going missing anywhere.

Inode

Filesystem Object Count

Every file, folder, and email on your account counts as one inode. Hosting plans often cap the total, separately from disk space.

IOPS

Input/Output Operations Per Second

A measure of how many read/write operations a drive can handle per second — often a better indicator of real-world performance than raw storage size.

IPv4

Internet Protocol version 4

The older, still widely used addressing scheme, written as four number groups like 192.0.2.1. We're gradually running out of these.

IPv6

Internet Protocol version 6

The newer addressing scheme built to solve IPv4's shortage problem, using a much longer format like 2001:db8::1.

JSON

JavaScript Object Notation

A lightweight, easy-to-read data format that's become the default for APIs and configuration files across most modern software.

Keyword

Search Term Target

A word or phrase you shape a page's content around, based on what people are actually typing into search engines when looking for something like it.

KVM

Kernel-based Virtual Machine

A virtualization module built into the Linux kernel that lets one physical server run several independent virtual machines with hardware-level isolation.

LAMP

Linux, Apache, MySQL, PHP

The classic open-source stack behind a huge share of the web, including WordPress in its default form.

LEMP

Linux, Nginx, MySQL/MariaDB, PHP/Python

Basically LAMP's sibling — same idea, but Nginx handles the web serving instead of Apache. ("Nginx" is pronounced "engine-x," which is where the E comes from.)

Let's Encrypt

Free Certificate Authority

A nonprofit CA that issues free, short-lived SSL/TLS certificates and renews them automatically — the reason most small sites run HTTPS by default now.

LLM

Large Language Model

A machine learning model trained on huge amounts of text so it can generate and understand natural language — the technology behind tools like chatbots and AI writing assistants.

Load Balancer

Traffic Distribution System

Spreads incoming requests across multiple servers so no single one gets overwhelmed, and can reroute traffic if a server goes down.

Log File

Activity Record

A running record of events on a server — errors, visits, login attempts — usually the first place to look when something's misbehaving.

LVE

Lightweight Virtual Environment

A per-account container that caps how much CPU and memory a single shared hosting account can consume, so one account having a bad day doesn't drag down everyone else on the server.

LXC

Linux Containers

A lighter form of virtualization where containers share the host's kernel instead of running their own. Faster to spin up than a full VM, though isolation is less strict.

Machine Learning

Pattern-Based Prediction

A branch of AI where a system improves at a task by learning patterns from data, rather than following rules a person wrote out step by step.

Mailbox Quota

Email Storage Limit

The maximum storage allowed for a single email account before new messages start bouncing.

Malware Scanner

Security Monitoring Tool

Software that checks your files for known malicious code patterns and flags or quarantines anything suspicious it finds.

Managed WordPress Hosting

WordPress-Optimized Hosting

A hosting environment tuned specifically for WordPress, usually bundling caching, automatic core updates, and staging tools so you're not configuring all of that by hand.

Meta Description

Search Result Snippet

The short summary text that shows up under a page's title in search results, written to encourage a click rather than to be read by the page's actual visitors.

Minification

Code Size Reduction

Strips unnecessary spacing and comments out of CSS and JavaScript files to make them smaller and faster to load, without changing what the code actually does.

ModSecurity

Open-Source WAF Engine

One of the most widely used engines powering web application firewalls on Apache and Nginx servers, often running quietly in the background of shared hosting.

MX

Mail Exchange Record

The DNS record that tells the internet which mail server is responsible for handling email for your domain.

MySQL / MariaDB

Database Software

The database engines behind most hosted websites, including WordPress by default. MariaDB started as a community fork of MySQL and is largely a drop-in replacement for it.

NAT

Network Address Translation

Lets devices on a private network share a single public IP address to reach the internet.

Nginx / Apache

Web Server Software

The two most common programs for actually serving your website's files and handling incoming HTTP requests.

NLP

Natural Language Processing

The broader field of AI focused on getting computers to understand, interpret, and generate human language.

NS / Nameserver

Name Server Record

Tells the internet which servers are authoritative for your domain's DNS — essentially, whose DNS records to trust and read.

NVMe

Non-Volatile Memory Express

A high-speed protocol for SSDs that connects directly to a system's high-bandwidth bus, making it noticeably faster than older SSD interfaces.

OAuth

Open Authorization

The standard behind "Log in with Google" style buttons, letting an app verify your identity without ever handling your actual password.

Object Caching

Database Query Caching

Stores the results of expensive database queries in memory, often using Redis or Memcached, so repeat requests skip hitting the database again — especially useful for dynamic sites like WordPress.

One-Click Installer

App Installation Tool

A control panel feature (Softaculous is the most common one) that installs WordPress and dozens of other apps in a couple of clicks, instead of manually uploading files and setting up a database yourself.

ONNX

Open Neural Network Exchange

An open file format for machine learning models, designed so a model trained in one framework can run in another without being rebuilt from scratch.

OPcache

PHP Opcode Cache

Stores precompiled PHP code in memory so the server doesn't have to recompile the same scripts on every single page load.

Overselling

Shared Resource Practice

When a host sells more storage/bandwidth than physically exists on a server, betting that not everyone will use their full allotment at once. Common in budget shared hosting.

PaaS / IaaS

Platform / Infrastructure as a Service

IaaS hands you raw compute and storage to build on; PaaS goes a step further and gives you a managed environment where you just deploy code.

Parked Domain

Domain Alias

An extra domain pointed at your existing site so it loads the same content — often used to hold onto alternate spellings or TLDs.

PEM

Privacy-Enhanced Mail

A common file format (.pem) for storing SSL certificates and private keys as base64-encoded text, despite the "mail" in the name having nothing to do with email anymore.

Permalink

Post/Page URL Structure

The actual URL format WordPress uses for your posts and pages, which you can customize for readability or SEO instead of leaving it as the default query-string style.

PHP-FPM

PHP FastCGI Process Manager

Manages how PHP handles multiple requests at once, generally making PHP-based sites (like WordPress) noticeably faster than older handling methods.

phpMyAdmin

Database Management Tool

A web-based interface for viewing and editing your MySQL/MariaDB databases directly, useful for quick fixes without writing raw SQL commands.

Ping / Latency

Response Time Measurement

Ping tests how long a round trip to a server takes; latency is the delay itself. Lower is better for anything time-sensitive.

Plugin

Add-On Functionality

A small piece of software you install into WordPress to add a specific feature — contact forms, SEO tools, caching, and so on — without editing the core code.

POP3

Post Office Protocol 3

Downloads email from the server to a single device and typically removes it from the server afterward.

Port

Network Communication Endpoint

A numbered channel on a server that specific services listen on — port 80 for HTTP, 443 for HTTPS, 22 for SSH, and so on.

Prompt

User Instruction

The text you type in to tell an AI model what you want it to do — the quality and detail of the prompt usually has a big effect on the quality of the answer.

PTR

Pointer Record

A DNS record used for reverse lookups — going from an IP address back to a domain name, which matters a lot for email deliverability.

RAG

Retrieval-Augmented Generation

An approach where an AI system looks up relevant information first, then uses that as grounding to write its answer, instead of relying only on what it memorized during training.

RAID

Redundant Array of Independent Disks

A way of combining multiple physical drives so data survives a single drive failure, gets faster read/write speeds, or both, depending on the RAID level in use.

RAID 0 / 1 / 5 / 10

RAID Levels

Different flavors of RAID. RAID 0 is pure speed with zero redundancy, RAID 1 mirrors drives for safety, and RAID 5/10 blend redundancy with performance.

RAM

Random Access Memory

Fast, short-term memory a server uses to hold active processes and data. Unlike storage, it's wiped clean on reboot.

RDAP

Registration Data Access Protocol

The modern, structured-data successor to WHOIS. ICANN has required it for gTLDs since 2019, but plenty of country-code domains still run WHOIS-only, so both are still in active use.

Reseller Hosting

Wholesale Hosting Model

Lets you buy server resources in bulk and resell smaller hosting packages to your own clients, usually through white-labeled cPanel accounts.

REST

Representational State Transfer

A common architectural style for APIs that uses standard HTTP methods like GET and POST to interact with resources.

Reverse Proxy

Traffic Router

Sits in front of one or more servers, routing requests, balancing load, caching responses, and shielding the backend from direct exposure.

robots.txt

Crawler Instructions File

A plain text file that tells search engine bots which parts of your site they're allowed, or not allowed, to crawl.

Root Access

Full Administrative Control

Unrestricted permission to modify anything on a server. Powerful, but a mistake at this level can take the whole box down — handle with care.

SaaS

Software as a Service

An application that runs on someone else's servers and is accessed through a browser or API — think webmail or a hosted CRM. There's no server for you to patch or maintain.

SAN Certificate

Subject Alternative Name / Multi-Domain Certificate

An SSL certificate that covers several entirely different domains under one certificate, rather than just subdomains of a single root domain.

SCP

Secure Copy Protocol

Copies files between machines over an encrypted SSH connection — simple, but has largely been overtaken by SFTP for regular use.

SEO

Search Engine Optimization

The practice of shaping a site's content, structure, and speed so it ranks higher in search results — everything from page titles to load times can factor in.

SFTP

SSH File Transfer Protocol

File transfer that rides over an encrypted SSH connection — essentially FTP's more secure replacement.

Shared Hosting

Multi-Tenant Hosting

The most common starting point for a new website — many accounts live on one server and split its CPU, RAM, and storage. It's affordable, though a busy "neighbor" site can occasionally slow things down for everyone else on the box.

Shortcode

Content Placeholder Tag

A short bracketed tag, like [gallery], that WordPress swaps out for a more complex piece of content or functionality when the page renders.

Site Migration

Hosting Transfer

Moving a website's files, databases, and settings from one host — or one server — to another, ideally without visitors noticing any downtime.

Sitemap.xml

Site Structure File

An XML file listing your site's pages so search engines can discover and index them more efficiently.

SLA

Service Level Agreement

A host's formal commitment around uptime, support response times, or performance — and what they'll do (often an account credit) if they don't hit it.

SMTP

Simple Mail Transfer Protocol

The protocol used to send email out from a mail server — it's the "sending" half of the email system.

SNI

Server Name Indication

Lets a single IP address serve valid SSL certificates for multiple different domains, which is a big part of why shared hosting with HTTPS works at scale.

SOA Record

Start of Authority Record

Holds the administrative details for a domain's DNS zone, including the primary nameserver and how often other servers should check in for updates.

Social Media Integration

Cross-Platform Connection

Tools or plugins that connect a website to its social accounts — share buttons, embedded feeds, or auto-posting new content out to those platforms.

Spam Filter

Unwanted Mail Screening

Scans incoming mail for spam characteristics and routes suspicious messages to a junk folder instead of the main inbox.

SPF

Sender Policy Framework

A DNS record that lists which mail servers are allowed to send email on behalf of your domain, helping prevent spoofed messages.

SSD / HDD

Solid-State Drive / Hard Disk Drive

SSDs use flash memory and have no moving parts, so they're fast and durable. HDDs use spinning magnetic platters — slower, but cheaper per gigabyte.

SSH

Secure Shell

The standard way to log into a remote server securely, whether you're running commands or transferring files.

ssh_config

SSH Client Configuration File

Lets you save shortcuts for servers you connect to often, so you're not retyping hostnames, ports, and usernames every time.

SSL / TLS

Secure Sockets Layer / Transport Layer Security

The encryption that puts the "S" in HTTPS. TLS is technically the modern successor to SSL, but people still say "SSL certificate" out of habit.

Staging Environment

Pre-Production Copy

A private copy of your live site where you can test changes, updates, or new plugins before pushing them to visitors.

Static Content Caching

Page-Level Caching

Stores a ready-to-serve copy of unchanging elements — images, CSS, full HTML pages — so the server can hand them out instantly instead of regenerating them on every request.

Subdomain

Domain Subdivision

A prefix added to your main domain (like blog.yoursite.com) that can point to a different folder or even a different app entirely.

Sudo

Superuser Do

Lets a regular user run a specific command with root-level permissions, usually after entering their own password.

Symlink

Symbolic Link

A shortcut file that points to another file or folder elsewhere on the system, keeping both locations in sync without actually duplicating the data.

Theme

Site Design Template

Controls how a WordPress site looks — layout, colors, fonts — while keeping the underlying content separate, so you can switch designs without losing your posts and pages.

TLD

Top-Level Domain

The suffix at the end of a domain — .com, .org, .net, and so on.

Token

Text Processing Unit

The small chunks (often pieces of words) that an AI model breaks text into to process it — and usually what API pricing is actually billed by.

Traceroute

Network Path Diagnostic

Maps every hop a data packet takes to reach its destination — useful for figuring out where a connection is actually slowing down.

Training Data

Model Learning Material

The large collection of text, images, or other examples an AI model learns from before it's released — its knowledge is shaped entirely by what was in that data.

TTFB

Time To First Byte

How long it takes the server to send back the very first byte of a response after a request comes in — a common early diagnostic when a site "feels slow."

TTL

Time-To-Live

How long, in seconds, a DNS record is cached before systems check for an updated version. Lower TTLs mean changes propagate faster.

TXT Record

Text Record

A flexible DNS record type used to store arbitrary text — most commonly for domain ownership verification, and it's what SPF, DKIM, and DMARC entries actually live in behind the scenes.

UFW

Uncomplicated Firewall

A friendlier front end for Linux's firewall rules — handy if you want basic protection without wrestling with iptables directly.

UPS

Uninterruptible Power Supply

A battery backup system that keeps servers running through short power outages and gives generators time to kick in during longer ones.

Uptime

Availability Percentage

The share of time your site is actually reachable. A host advertising "99.9% uptime" is still technically allowing for a little downtime every month — the math works out to under 45 minutes.

Varnish

HTTP Cache / Accelerator

Sits in front of your web server and serves cached copies of pages directly, often skipping the backend entirely for repeat visitors.

vCPU

Virtual Central Processing Unit

A virtual representation of a CPU core assigned to a VM. The physical core underneath may be shared across several vCPUs.

VDS

Virtual Dedicated Server

Similar idea to a VPS, but the hardware resources are locked to you specifically rather than shared with other tenants on the host.

Vector Database

Similarity Search Store

A database built to store embeddings and quickly find the closest matches to a query — the backbone of most RAG systems.

VPN

Virtual Private Network

Creates an encrypted tunnel between your device and a remote network, often used to securely reach server admin tools that aren't meant to be exposed publicly.

VPS

Virtual Private Server

A slice of a physical server that acts like its own machine, with a dedicated OS, CPU allocation, RAM, and storage. You get root access without paying for a whole physical box.

WAF

Web Application Firewall

Filters and blocks malicious HTTP traffic — SQL injection attempts, bad bots, and known exploit patterns — before it ever reaches your application.

Webhook

Event-Triggered Callback

Automatically sends data to another system the moment something happens — like notifying a Slack channel the instant a form is submitted.

Webmail

Browser-Based Email Client

Lets you check and send email through a web browser instead of a dedicated app like Outlook — no setup required, just log in.

Website Analytics

Visitor Tracking

Software that reports on who's visiting a site, where they came from, and what they did once they arrived — the data most marketing decisions end up leaning on.

Website Builder

Drag-and-Drop Tool

A visual, no-code way to put a site together, often included with shared hosting plans as a simpler alternative to installing and configuring a full CMS.

White Screen of Death

Blank Page Failure

WordPress shorthand for when a site loads to a completely blank white page with no error message, usually caused by a plugin conflict or a PHP memory limit issue.

WHOIS

Domain Lookup Service

A public lookup you can run to see who registered a domain and when (though privacy protection often hides the personal details now).

Widget

Sidebar/Footer Element

A small, self-contained block of content or functionality — a calendar, a search bar, recent posts — that you drag into predefined areas of a theme like sidebars or footers.

Wildcard SSL

Multi-Subdomain Certificate

A single SSL certificate that covers a domain and all of its subdomains at once (like *.yoursite.com), so you're not issuing a separate certificate every time you add a new subdomain.

WordPress Multisite

Multi-Site Network

A single WordPress installation that runs several separate sites at once, sharing one dashboard, one set of plugins, and one codebase.

WP-CLI

WordPress Command Line Interface

Lets you manage a WordPress site — installing plugins, running updates, managing users — entirely through terminal commands over SSH instead of clicking through the dashboard.

wp-config.php

Core Configuration File

The file that holds a WordPress site's database connection details and core settings. Editing it carelessly is one of the most common ways to accidentally take a site down.

XML

eXtensible Markup Language

An older, more verbose data format than JSON, still widely used for things like sitemaps, RSS feeds, and legacy API integrations.

YAML / YML

YAML Ain't Markup Language

A config file format built to be readable by humans, not just machines — widely used for things like CI pipelines and app settings.

2FA / MFA

Two-Factor / Multi-Factor Authentication

Requires a second proof of identity beyond your password, usually a code from an app or text message, before letting you log in.

400 Bad Request

Malformed Request Error

The server couldn't understand the request as sent, often due to bad syntax somewhere in the URL or the submitted data.

401 Unauthorized

Authentication Required Error

The server is asking you to log in — or log in correctly — before it will show you what you asked for.

403 Forbidden

Access Denied Error

The server found what was requested but is refusing to show it, often due to file permission settings or a security rule blocking the request.

404 Not Found

Missing Page Error

The server understood the request but couldn't find anything at that address — usually a broken link, a deleted page, or a typo in the URL.

500 Internal Server Error

Generic Server Failure

A catch-all error meaning something went wrong on the server's end, without specifying what — often traced back to a broken script or a corrupted .htaccess file.

502 Bad Gateway

Upstream Server Error

One server acting as a gateway got an invalid response from another server it was relying on — common when a reverse proxy or load balancer can't reach the backend.

503 Service Unavailable

Temporary Outage Error

The server is up but temporarily can't handle the request, often due to maintenance or being overloaded with traffic.

504 Gateway Timeout

Upstream Timeout Error

Similar to a 502, but here the upstream server simply took too long to respond and the request timed out waiting.