Glossary
Web words, without the jargon.
Every term you'll meet in our case files and lessons, explained in one or two sentences.
A
- Above the fold
- What you see on screen before you scroll.
- Why it matters: Visitors decide whether to stay based mostly on this part.
- Accessibility
- How well people with disabilities can use a website, including people who are blind, deaf, colour-blind or can't use a mouse.
- Why it matters: About one in six people has a disability. Accessible sites are easier for everyone.
- Alt text
- A short written description of an image, read aloud by screen readers and shown if the image fails to load.
B
- Breakpoint
- A screen width at which a website changes its layout, for example from three columns to one on a phone.
C
- Cache
- A saved copy of files that lets a page load faster the second time.
- Call to action (CTA)
- The main thing a page asks you to do, usually a button such as "Book now".
- Why it matters: One clear call to action converts better than several competing ones.
- CDN
- Content delivery network: servers around the world that store copies of a site so it loads quickly everywhere.
- Colour contrast
- How different the text colour is from the background. Measured as a ratio such as 4.5:1.
- Why it matters: Low contrast is one of the most common and easiest problems to fix.
- Conversion
- When a visitor does what the site wants: books, buys, calls or signs up.
- Core Web Vitals
- Google's three speed and stability measures: how fast the main content appears, how quickly the page reacts, and how much it jumps around.
D
- Domain
- The website's address, such as webpo.org.
F
- Favicon
- The small icon shown in the browser tab next to the page title.
H
- Hierarchy
- Making the most important thing on the page the most noticeable, through size, colour and position.
- HTTPS
- The secure version of a web address. Browsers show "Not secure" when a site doesn't use it.
- Why it matters: Free to set up on most hosts, and visitors trust it.
L
- Lighthouse
- A free tool built into Chrome that scores a page for speed, accessibility, SEO and best practice.
- Lorem ipsum
- Fake placeholder text used while designing. It should never be on a live site.
M
- Meta description
- The short summary under a page's title in search results.
- Mixed content
- A secure (HTTPS) page that loads some files insecurely. Browsers may block them or show a warning.
P
- Page title
- The text in the browser tab and the blue link in search results.
- Page weight
- The total size of everything a page downloads. Lighter pages load faster, especially on phones.
R
- Responsive design
- A website that adapts its layout to any screen size, from phone to desktop.
- Right to left (RTL)
- Languages such as Arabic and Hebrew that are read from right to left. The whole layout should mirror.
S
- Screen reader
- Software that reads a website aloud for people who are blind or have low vision.
- SEO
- Search engine optimisation: making a site easy for search engines to understand and show to the right people.
- Sitemap
- A file listing all the pages on a site, so search engines can find them.
- SSL certificate
- The file that makes HTTPS work. It expires and must be renewed, usually automatically.
T
- Tap target
- Anything you tap on a phone, such as a button or link. It should be at least 44 by 44 pixels.
- Typography
- How text looks: fonts, sizes, spacing and line length.
V
- Viewport
- The visible area of a web page on a particular screen.
- Visual weight
- How strongly something draws the eye, based on its size, colour and contrast.
W
- WCAG
- Web Content Accessibility Guidelines: the international standard for accessible websites. Level AA is the usual target.
- Whitespace
- Empty space between and around things on a page. It makes content easier to scan.