A
- Alt Text
- The
alt attribute on an <img> element. Read by screen readers, indexed by search engines, shown when images fail. See our alt text guide.
- AMP (Accelerated Mobile Pages)
- A stripped-down HTML format for fast-loading mobile pages. Largely deprecated since 2021 when Google removed the AMP requirement for mobile carousels. Most sites have moved off AMP.
- Anchor Text
- The visible, clickable text of a hyperlink. One signal search engines use to understand the destination's topic.
- aria-label
- An accessibility attribute that provides an accessible name for an element when its visible text isn't sufficient. Used heavily on icon-only buttons.
B
- Breadcrumb
- A navigational element showing a page's position in the site hierarchy. Marked up with schema.org BreadcrumbList for rich snippets.
C
- Canonical Tag
<link rel="canonical"> — tells search engines which URL to index when multiple URLs serve the same content. See our canonical guide.
- Card (Twitter/X)
- The rich preview rendered by X when a URL is shared. Configured via
<meta name="twitter:..."> tags. See our Twitter Cards guide.
- Charset
<meta charset="UTF-8"> — declares the character encoding of the document. Should always be UTF-8 in modern HTML.
- CTR (Click-Through Rate)
- The percentage of search impressions that result in a click. Title and meta description quality directly influence CTR.
D
- Description (Meta)
<meta name="description"> — the short summary shown in search snippets. Doesn't directly affect rankings but heavily influences CTR. See our meta description guide.
- Duplicate Content
- The same or near-identical content appearing at multiple URLs. Search engines need to choose one to index; canonical tags tell them which.
F
- Favicon
- The small icon displayed in browser tabs and bookmarks. Declared via
<link rel="icon">.
H
- H1, H2, H3 (Heading Tags)
- HTML elements that structure the page's outline. One H1 per page; H2s for major sections; H3s for sub-sections. See our heading hierarchy guide.
- hreflang
<link rel="alternate" hreflang="..."> — declares the language and region of a page, helping search engines serve the right version to multilingual audiences.
I
- Indexed
- A URL is "indexed" when search engines have it in their searchable database. Pages can be excluded via
noindex or by URL parameter rules.
J
- JSON-LD
- The recommended format for embedding schema.org structured data. Wrapped in
<script type="application/ld+json"> in the page head. Powers rich snippets in search results.
K
- Keyword Stuffing
- Cramming target keywords into meta tags or content to manipulate rankings. Worked in 2010, penalised since. Don't.
- Keywords (Meta)
<meta name="keywords"> — historically used by search engines, ignored by Google since 2009. Safe to omit on modern sites.
L
- Lang Attribute
<html lang="en"> — declares the page's primary language. Improves accessibility (screen reader pronunciation) and helps search engines choose the right region.
M
- Meta Tag
- An HTML
<meta> element in the document head, providing metadata about the page. Includes description, keywords, viewport, robots, charset, OG, Twitter, and many others.
N
- nofollow
rel="nofollow" on a link — tells search engines not to pass link equity to the destination. Used historically to mark untrusted or sponsored links.
- noindex
<meta name="robots" content="noindex"> — explicitly tells search engines not to index this page. Use for admin pages, thank-you pages, internal search results.
O
- Open Graph (OG)
- A meta tag protocol originally created by Facebook, now used by Facebook, LinkedIn, Slack, Discord, and as a fallback by Twitter/X. Tags start with
og:.
- OG Image
<meta property="og:image"> — the image shown when a URL is shared on social platforms. Recommended dimensions: 1200×630 pixels.
R
- Rich Snippet
- A search result with extra visual elements (rating stars, FAQs, breadcrumbs) generated from structured data on the page.
- Robots Meta Tag
<meta name="robots"> — instructions to search engine crawlers. Common values: index, follow (default), noindex, nofollow, noarchive.
- robots.txt
- A file at
/robots.txt telling crawlers which URLs to skip. Different from the robots meta tag — robots.txt is at the URL level; the meta tag is at the page level.
S
- schema.org
- A vocabulary of structured data types (Article, Product, Recipe, Event, Person, etc.) used by search engines to understand page content. Embedded as JSON-LD.
- SERP (Search Engine Results Page)
- The page of results returned by a search engine. Title, description, and structured data control how your URL appears on the SERP.
- Sitemap
- An XML file at
/sitemap.xml listing the canonical URLs on your site, submitted to search engines for crawl prioritisation.
- Structured Data
- Machine-readable data describing page content, typically in JSON-LD format following the schema.org vocabulary. Powers rich snippets.
T
- Title Tag
- The
<title> element in the page head. The most prominent on-page SEO signal. See our title tag guide.
U
- UTM Parameters
- URL parameters (utm_source, utm_medium, utm_campaign) used by analytics tools to attribute traffic. Don't break the page but should be excluded from canonical URLs.
V
- Viewport Meta Tag
<meta name="viewport" content="width=device-width, initial-scale=1.0"> — controls how the page renders on mobile devices. Required for responsive design.