Resources/Glossary

SEO Glossary

62 SEO terms, defined clearly

Technical SEO, redirects, title tags, E-E-A-T, AI search, and revenue attribution. Every term comes with a full definition, a worked example, and answers to the questions practitioners actually ask.

Technical SEO

Canonical Tag

Tells search engines which URL is the preferred version.

Duplicate Content

Substantially similar content on multiple URLs.

Hreflang

HTML attribute signaling page language and region.

Schema Markup

Structured data (JSON-LD) that helps search engines understand content.

Core Web Vitals

Google's LCP, INP, CLS page-experience metrics.

Crawl Budget

How often/many pages Googlebot crawls on your site.

Indexability

Whether a page can be stored in Google's index.

robots.txt

File telling crawlers which URLs they can access.

Title Tag

The HTML <title> element that names a page — shown as the blue headline in search results and used as a primary on-page ranking signal.

Meta Description

The HTML snippet (160 chars) that summarises a page below its title in search results. Not a ranking signal but directly affects CTR.

301 Redirect

A permanent HTTP redirect that passes ~99% of link equity from the old URL to the new one. The correct redirect type for site migrations and URL changes.

Redirect Chain

Two or more consecutive redirects between a source URL and its final destination. Chains lose link equity at each hop and slow page load.

Noindex Tag

A robots meta tag (content="noindex") that instructs search engines not to include a page in their index. The page is crawlable but will not appear in search results.

XML Sitemap

A structured file (sitemap.xml) that lists a site's URLs so search engines can discover and prioritise them for crawling.

H1 Tag

The top-level HTML heading that names the main topic of a page. One clear H1 per page anchors the heading hierarchy for crawlers, accessibility tools, and AI systems.

Alt Text

The alt attribute describing an image for screen readers and search engines. The foundation of image SEO and an accessibility requirement.

Open Graph Tags

Meta tags (og:title, og:image, og:description) that control how a page renders when shared on social platforms, chat apps, and link previews.

Meta Robots Tag

An HTML meta tag giving crawlers page-level indexing instructions: noindex, nofollow, noarchive, nosnippet. Controls what crawlers do after fetching a page.

JavaScript SEO

Making JavaScript-rendered content crawlable and indexable. Critical for React, Vue, and Angular sites where content renders client-side.

AI Search

AEO (Answer Engine Optimization)

Optimization for AI answer engines like ChatGPT, Perplexity, AI Overviews.

GEO (Generative Engine Optimization)

Content structured for LLM retrieval and citation.

LLM Visibility

How often a brand is cited in LLM outputs.

Entity SEO

Optimization around Google's Knowledge Graph entities.

Knowledge Graph

Google's database of real-world entities and relationships.

AI Overviews

Google's AI-generated answers shown above organic results, with citation links to sources. Being cited in them is the new position zero.

AI Citation

A reference to a brand or page inside an AI-generated answer. The unit of visibility in answer engines: AEO counts citations the way SEO counts rankings.

Generative Engine Optimization (GEO)

The practice of structuring content for retrieval, citation, and accurate representation inside large language model-generated answers.

LLMO (LLM Optimization)

The practice of shaping content and brand presence so large language models accurately represent and cite a brand in their outputs.

RAG (Retrieval-Augmented Generation)

An LLM architecture that retrieves live documents before generating an answer, making cited sources the unit of visibility for RAG-powered search.

Vector Embeddings

Numerical representations of text meaning used by AI search engines to match queries to semantically similar content rather than exact keywords.

Semantic Search

Search that understands meaning, context, and entity relationships rather than matching exact keyword strings.

llms.txt

A plain-text file at the domain root that tells AI crawlers which pages to use when generating LLM-friendly summaries of a site.

Zero-Click Search

A search session that ends without any click to a website because the SERP or AI answer satisfied the query directly.

AI Search

Search experiences powered by large language models — including Google AI Overviews, ChatGPT search, Perplexity, and Microsoft Copilot — that generate answers rather than just rank links.

Grounding / Source Attribution

The process by which an AI system anchors its answer to specific retrieved sources, reducing hallucination and surfacing citable pages.

Query Fan-Out

Google AI Mode's technique of breaking a single user query into multiple sub-queries to retrieve richer, more comprehensive context before generating an answer.

Share of Model

The frequency with which a brand is mentioned or cited by large language models relative to competitors — the AI-era equivalent of share of voice.

ChatGPT / Perplexity SEO

Optimizing content and brand presence specifically for citation in ChatGPT search and Perplexity AI answers, where retrieval-based selection determines visibility.

Put the knowledge to work

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