SEO has an extensive vocabulary that can be bewildering for beginners and occasionally confusing even for experienced practitioners as terminology evolves. This glossary covers every significant term you will encounter in 2026 — from foundational concepts to current AI-era terminology.
A – C
Algorithm — Google's system for evaluating and ranking web pages. Not a single algorithm but hundreds of signals processed simultaneously. See our guide to algorithm update history.
Alt Text — descriptive text in the alt attribute of an image HTML tag. Helps search engines understand image content and assists visually impaired users. See our complete guide to writing alt text.
Anchor Text — the clickable, visible text of a hyperlink. A key relevance signal for the linked page. See our guide to anchor text strategy.
Backlink — a link from another website pointing to yours. One of the strongest ranking signals. See our guide to backlink profile audits.
Black Hat SEO — techniques that violate Google's guidelines. See our guide to black hat SEO risks.
Bounce Rate — percentage of sessions where users view only one page. See our guide to bounce rate and SEO.
Canonical Tag — HTML element specifying the preferred URL when duplicate content exists. See our guide to canonical tags.
Core Web Vitals — Google's page experience metrics: LCP, INP, and CLS. See our guide to Core Web Vitals in 2026.
Crawl Budget — the number of pages Googlebot will crawl on your site in a given period. See our guide to crawl budget.
CTR (Click-Through Rate) — percentage of impressions that result in clicks. See our guide to improving CTR.
D – G
Disavow Tool — Google's tool for asking it to ignore specific backlinks. See our guide to using the disavow tool.
Domain Authority (DA) — Moz's metric predicting ranking potential. See our guide to domain authority.
Duplicate Content — identical or near-identical content appearing on multiple URLs. See our guide to fixing duplicate content.
E-E-A-T — Experience, Expertise, Authoritativeness, Trustworthiness. Google's quality evaluation framework. See our guide to E-E-A-T.
Featured Snippet — highlighted answer box appearing above organic results. See our guide to optimising for featured snippets.
Google Search Console — free tool showing how Google sees your site. See our guide to Google Search Console.
H – L
Hreflang — HTML attribute specifying language and country targeting. See our guide to international SEO.
Internal Link — link from one page to another page on the same domain. See our guide to internal linking strategy.
Keyword Cannibalisation — multiple pages competing for the same keyword. See our guide to fixing keyword cannibalisation.
Link Equity — authority passed from one page to another through links. See our guide to link equity.
M – R
Meta Description — HTML tag summarising page content for search results. See our guide to meta descriptions.
Mobile-First Indexing — Google uses the mobile version of pages for ranking. See our guide to mobile-first indexing.
Nofollow — link attribute instructing search engines not to follow a link. See our guide to dofollow vs nofollow.
Orphan Page — page with no internal links pointing to it. See our guide to finding orphan pages.
PageRank — Google's link authority algorithm. See our guide to PageRank.
Redirect — sending users and crawlers from one URL to another. See our guides to 301 redirects and redirect chains.
Robots.txt — file controlling which pages crawlers can access. See our guide to robots.txt.
S – Z
Schema Markup — structured data code helping search engines understand content. See our guide to schema markup.
Sitemap — file listing URLs on your site for search engines. See our guide to building sitemaps.
Thin Content — pages providing little or no value to users. See our guide to thin content.
Topical Authority — Google's assessment of how comprehensively a site covers a subject. See our guide to topical authority.
YMYL (Your Money or Your Life) — content categories with strictest quality requirements. See our guides to healthcare and finance SEO.
Zero-Click Search — queries answered within search results without a click. See our guide to zero-click search.
Missed the previous article? Read: 10 SEO Myths That Are Wasting Your Time and Budget in 2026