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SEO Glossary

51 essential SEO terms explained in plain English. The terms you'll encounter when reading SEO blogs, hiring an agency, or running your own programme.

Sorted alphabetically. If a term you need is missing, tell us and we'll add it.

Algorithm
The set of rules Google uses to rank pages. Updated dozens of times per year.
Alt text
Descriptive text on an image. Used by screen readers and as a ranking signal.
Anchor text
The visible, clickable text in a hyperlink. A ranking signal for the linked page.
Authority
A subjective measure of a domain’s trust and ranking power, derived from backlinks.
Backlink
A link from another website to yours. Often called an inbound link.
Black-hat SEO
Tactics that violate Google guidelines (link buying, cloaking, content spinning). Risky and short-term.
Bounce rate
Percentage of visitors who leave after one page. Imperfect signal — high bounce can mean satisfaction.
Canonical tag
HTML tag telling Google which version of a duplicated URL is the canonical one.
Click-through rate (CTR)
Percentage of impressions that resulted in a click. A strong indirect ranking signal.
Cloaking
Showing different content to search engines vs users. Against guidelines.
Content gap
A topic competitors cover but you don’t. Common keyword research output.
Core Web Vitals
Google’s page-experience metrics: LCP, INP, CLS. Confirmed ranking factors.
Crawl
How Googlebot follows links and reads pages.
Crawl budget
How many pages Google will crawl on your site per visit. Matters for large sites only.
Direct traffic
Visitors arriving without a referrer (typed URL, bookmark, app link).
Domain authority (DA)
Moz’s 1–100 trust score. Useful as a comparative metric, not a Google signal.
Dwell time
How long a visitor stays on your page after clicking from search.
E-E-A-T
Experience, Expertise, Authoritativeness, Trustworthiness. Quality framework Google emphasises.
Featured snippet
Box at the top of search results with an extracted answer. Position zero.
Google Business Profile (GBP)
Free local listing on Google. Critical for near-me visibility.
H1, H2, H3
HTML heading tags. H1 is the page’s primary heading; H2/H3 structure sub-sections.
Indexation
Google having your page in its searchable index. No index = no rankings.
Internal link
A link from one page on your site to another. Underused ranking lever.
Keyword
The search term a user types.
Keyword cannibalisation
Multiple pages on your site competing for the same keyword. Usually hurts both.
Keyword difficulty (KD)
A 0–100 score estimating how hard a keyword is to rank for. Read the KD guide.
Link equity
The ranking power passed through a link. Sometimes called link juice.
Local pack
The map + 3 listings shown for local queries. Separate algorithm from organic.
Long-tail keyword
A specific 3+ word query. Lower volume, higher intent, easier to rank.
Meta description
The short snippet under your title in search results. Not a ranking factor, but affects CTR.
NAP
Name, Address, Phone. Must match exactly across local citations.
Nofollow
A link attribute telling Google not to follow it for ranking. Defaults on most user-submitted content.
Off-page SEO
Everything you do outside your site to influence rankings — mainly backlinks and brand mentions.
On-page SEO
Everything you do on the page itself — title, headings, content, internal links, structured data.
Organic traffic
Visitors arriving from unpaid search results.
PageRank
Google’s original link-based ranking algorithm. Still relevant in a much-evolved form.
Pillar page
A long, comprehensive page on a broad topic, supported by linked cluster pages.
Rank tracker
A tool that monitors your position over time for chosen keywords. Try our free rank checker.
Redirect (301/302)
301 = permanent move, 302 = temporary. Use 301 unless you genuinely mean temporary.
Referring domain
A unique website linking to yours. More valuable as a count than total backlinks.
Rich result
Enhanced search listing with stars, FAQs, sitelinks, etc. Triggered by structured data.
Robots.txt
A file telling crawlers which paths to skip.
Schema markup
Structured data (usually JSON-LD) describing your page’s content type.
SERP
Search Engine Results Page. The page you see after a Google search.
Site audit
A health-check of your site’s SEO basics. Run our free site audit.
Sitemap
An XML file listing all your URLs for search engines.
TF-IDF
A term-weighting model. Modern Google uses something more sophisticated, but the principle still helps content depth.
Title tag
The page’s primary on-page SEO signal. Lead with the keyword.
Topical authority
Google’s sense that your site is a credible source on a topic — built through depth and links.
White-hat SEO
SEO that follows Google’s guidelines. The only sustainable approach.
Zero-click search
A query Google answers directly in the SERP without anyone clicking. Increasingly common.