Reference
The web acronyms cheat sheet
Every web abbreviation decoded — CMS, SSL, CDN, DNS, GA4, SEO, UX, and dozens more.
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The web loves abbreviations. This page decodes every one you're likely to encounter — sorted alphabetically so you can find any acronym in seconds.
Quick summary
This page is a quick-reference list of 80+ web acronyms. Each entry includes the full phrase and a one-line explanation. Click the links to go deeper. Use Ctrl+F / Cmd+F to find any acronym instantly.
A–C
| Acronym | Stands for | What it means |
|---|---|---|
| A/B test | A/B Testing | Showing two versions of a page to different visitors to see which performs better. |
| API | Application Programming Interface | A way for two pieces of software to talk to each other. |
| CDN | Content Delivery Network | A network of servers worldwide that serves your site's files from the location nearest to each visitor. See What is a CDN?. |
| CLS | Cumulative Layout Shift | A Core Web Vital measuring how much the page unexpectedly moves as it loads. |
| CMS | Content Management System | Software (WordPress, Webflow, etc.) that lets you edit your website without writing code. |
| CPC | Cost Per Click | The price you pay for each click in a paid ad campaign. |
| CPM | Cost Per Mille | The price you pay per 1,000 ad impressions. |
| CRM | Customer Relationship Management | Software for managing contacts, leads, and client communication. |
| CSS | Cascading Style Sheets | Code that controls the visual appearance of a web page — colors, fonts, layout. |
| CTA | Call to Action | A prompt asking visitors to do something: "Book a call," "Buy now." |
| CTR | Click-Through Rate | The percentage of people who clicked on something (a link, ad, or search result) compared to how many saw it. |
D–F
| Acronym | Stands for | What it means |
|---|---|---|
| DKIM | DomainKeys Identified Mail | An email authentication method that digitally signs outgoing emails. See DKIM records, explained. |
| DMARC | Domain-based Message Authentication, Reporting & Conformance | Email policy that controls what happens when SPF or DKIM fail. See DMARC records, explained. |
| DNS | Domain Name System | The internet's address book, translating domain names to IP addresses. See What is DNS?. |
| DDoS | Distributed Denial of Service | An attack that floods a server with traffic to knock it offline. |
| E-E-A-T | Experience, Expertise, Authoritativeness, Trustworthiness | Google's framework for evaluating content quality. |
| FCP | First Contentful Paint | A speed metric measuring when the first content appears on screen during page load. |
| FTP | File Transfer Protocol | A method for transferring files to and from a server. |
| FSE | Full Site Editing | The WordPress feature set for editing your entire site design with blocks. |
G–I
| Acronym | Stands for | What it means |
|---|---|---|
| GA4 | Google Analytics 4 | The current version of Google Analytics. See What is Google Analytics (GA4)?. |
| GTM | Google Tag Manager | A tool for managing tracking scripts without code changes. See What is Google Tag Manager?. |
| HTML | HyperText Markup Language | The code that structures web pages. |
| HTTP | HyperText Transfer Protocol | The protocol for transferring data on the web. |
| HTTPS | HyperText Transfer Protocol Secure | The encrypted version of HTTP. See SSL & HTTPS, explained. |
| IMAP | Internet Message Access Protocol | The protocol that syncs email across devices — keeps email on the server. |
| INP | Interaction to Next Paint | A Core Web Vital measuring how quickly a page responds to user input. |
J–N
| Acronym | Stands for | What it means |
|---|---|---|
| JS | JavaScript | The programming language that makes web pages interactive. |
| KPI | Key Performance Indicator | A metric that measures progress toward an important goal. |
| LCP | Largest Contentful Paint | A Core Web Vital measuring when the main visible content loads. See Core Web Vitals explained. |
| LTV | Lifetime Value | The total revenue a customer is expected to generate over time. Also CLV (Customer Lifetime Value). |
| MFA | Multi-Factor Authentication | Logging in with multiple forms of verification. See Two-factor authentication, explained. |
| MX | Mail Exchange | A DNS record type that directs email to the right mail server. |
O–R
| Acronym | Stands for | What it means |
|---|---|---|
| PCI-DSS | Payment Card Industry Data Security Standard | Security standards for businesses handling card payments. See PCI compliance, in plain English. |
| PHP | PHP: Hypertext Preprocessor | The programming language WordPress is built on. |
| POP3 | Post Office Protocol 3 | An older email protocol that downloads messages to one device. Mostly replaced by IMAP. |
| ROI | Return on Investment | The benefit gained relative to cost. |
| RSS | Really Simple Syndication | A format for distributing regularly updated content — blog posts, podcast episodes. |
S–Z
| Acronym | Stands for | What it means |
|---|---|---|
| SaaS | Software as a Service | Software delivered via a subscription over the internet — no installation needed. |
| SERP | Search Engine Results Page | The page you see after a Google search. |
| SEO | Search Engine Optimization | Improving a site to appear higher in organic search results. See What is SEO?. |
| SFTP | Secure File Transfer Protocol | Encrypted version of FTP for secure file transfers. |
| SKU | Stock Keeping Unit | A unique code for each product (or variant) in your inventory. |
| SMTP | Simple Mail Transfer Protocol | The protocol used for sending email. See What is SMTP?. |
| SPF | Sender Policy Framework | A DNS record listing authorized email-sending servers for your domain. See SPF records, explained. |
| SQL | Structured Query Language | The language used to communicate with databases. WordPress uses MySQL. |
| SSH | Secure Shell | An encrypted way to remotely access a server's command line. |
| SSL | Secure Sockets Layer | The old name for the encryption technology now called TLS. Powers HTTPS. |
| TLD | Top-Level Domain | The domain extension — .com, .org, .net, .io. |
| TLS | Transport Layer Security | The modern encryption protocol behind HTTPS (updated version of SSL). |
| TTL | Time To Live | How long a DNS record is cached before servers re-check it. |
| UI | User Interface | The visual elements users interact with on a site or app. |
| URL | Uniform Resource Locator | A complete web address — https://yoursite.com/about-us. |
| UX | User Experience | The overall experience of using a website — usability, flow, feel. |
| UTM | Urchin Tracking Module | Parameters added to URLs to track traffic sources in analytics. See UTM links for campaign tracking. |
| VPN | Virtual Private Network | Encrypts your internet connection and hides your IP address. |
| VPS | Virtual Private Server | A hosting tier offering dedicated server resources without a full dedicated machine. |
| WAF | Web Application Firewall | A firewall specifically for filtering malicious web traffic. |
| WCAG | Web Content Accessibility Guidelines | International standards for web accessibility. |
| WYSIWYG | What You See Is What You Get | An editor where the preview looks like the final output. |
| XML | Extensible Markup Language | A file format used for sitemaps and data interchange. |
Common questions
Related guides
- Web basics: terms A–Z
- How the web works, in 5 minutes
- SEO: terms A–Z
- Domains & DNS: terms A–Z
- Security: terms A–Z
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