The website terms, in plain English

The words that come up in our guides, scans and quotes, and what they mean for your business.

301 redirect: An instruction that a page has moved permanently to a new address. Browsers and search engines follow it, and Google treats the new page as the old one's replacement. Read: Moving from WordPress to a modern website without losing your Google rankings
Accessibility overlay: A script added to a site that offers visitors display controls and tries to patch accessibility problems as the page loads. It can't fix the page's underlying code. Read: Why accessibility overlays don't make you compliant
ADA: The Americans with Disabilities Act, the US civil rights law that bars discrimination on the basis of disability. Title III covers businesses open to the public. Read: ADA website compliance for small businesses: what the law says in 2026
Alt text: A short text description of an image, read aloud by screen readers and shown if the image doesn't load.
CDN (content delivery network): A network of servers in many cities that keeps copies of a site's files, so each visitor is served from one close to them.
CLS (Cumulative Layout Shift): One of Google's Core Web Vitals: how much a page's content jumps around while it loads. Good is 0.1 or less. Read: Website speed and enquiries: what Core Web Vitals mean for a local business
CMS (content management system): Software for editing a website's content without writing code. WordPress, Drupal and Joomla are examples.
Core Web Vitals: Google's three measures of how a page feels to real visitors: loading (LCP), responsiveness (INP) and visual stability (CLS). Read: Website speed and enquiries: what Core Web Vitals mean for a local business
Content-Security-Policy: A security header that tells the browser which scripts, styles and images a page is allowed to load, which blocks many injected attacks. Read: Is your WordPress site a security risk? Plugins, PHP and what to check
End of life: The date after which a piece of software gets no more updates, including security fixes. Sites still running it keep working, with new weaknesses left open. Read: Drupal 7 is end of life: your options in 2026
HSTS (Strict-Transport-Security): A security header that tells browsers to only ever connect to the site over HTTPS.
INP (Interaction to Next Paint): One of Google's Core Web Vitals: how quickly a page responds when someone taps or clicks. Good is 200 milliseconds or less. Read: Website speed and enquiries: what Core Web Vitals mean for a local business
JSON-LD: The format for structured data that Google recommends: a block of code in a page describing what the page is about in a form machines can read.
LCP (Largest Contentful Paint): One of Google's Core Web Vitals: how long the main content of a page takes to appear. Good is 2.5 seconds or less. Read: Website speed and enquiries: what Core Web Vitals mean for a local business
Lighthouse: Google's free tool that loads a page in a test browser and scores its performance, accessibility, best practices and search basics out of 100.
llms.txt: A plain-text file at the root of a site that summarises it for AI assistants and links to its most useful pages.
PHP: The programming language WordPress, Drupal and Joomla are written in. Each version gets security fixes for a limited time. Read: Is your WordPress site a security risk? Plugins, PHP and what to check
Plugin: An add-on that gives a WordPress site a feature, such as a form, a slider or a booking calendar. Each one is code that has to be kept up to date.
Screen reader: Software that reads a screen aloud, or to a braille display, for people who are blind or have low vision.
Section 504: The part of the Rehabilitation Act that bars disability discrimination by anyone receiving federal funds. Its HHS rule sets WCAG 2.1 AA for healthcare providers' websites. Read: Healthcare websites and the HHS Section 504 rule: the deadlines
Security headers: Instructions a server sends with each page telling the browser how to protect visitors, such as always using HTTPS or which scripts to trust. Read: Is your WordPress site a security risk? Plugins, PHP and what to check
Static site: A website whose pages are built in advance and served as files, rather than assembled by a server and database for each visit. Faster, and with far less to attack.
Structured data: Information in a page's code that tells search engines and AI assistants exactly what something is: a business, its address, its opening hours, a question and its answer.
WCAG: The Web Content Accessibility Guidelines from the W3C, the standard for making websites usable by people with disabilities. Version 2.2 is current; level AA is the usual target. Read: WCAG 2.2 explained for business owners, with a checklist