The glossary grows a few terms at a time, starting with AI search, where the vocabulary is newest and most confused. Where two words mean the same thing, the definition says so.
3
301 RedirectSEO Fundamentals
A permanent redirect. Google reads it as a strong signal that the new URL should replace the old one.
A
Agentic SearchAI Search
Search where an AI agent works through the steps toward a goal for you, then hands back for you to confirm.
AI CrawlersAI Search
Bots run by AI companies that fetch web pages, either to train models, to power AI search or to answer one user's request.
AI HallucinationAI Search
A confident answer from an AI system that is false or not supported by any source.
AI OverviewsAI Search
Google's generated answer at the top of the results page, composed from several sources with links out.
Answer Engine OptimizationAI Search
Making your content the answer a search engine or assistant gives, rather than one link among ten.
C
Canonical TagSEO Fundamentals
A link element naming the preferred URL among duplicates. Google treats it as a strong hint, not a rule.
ChatGPT SearchAI Search
Web search inside ChatGPT, answering with live sources and links rather than memory alone.
Cumulative Layout ShiftSEO Fundamentals
How much content jumps around unexpectedly while a page loads. A score, not a time. Good is 0.1 or less.
G
Generative Engine OptimizationAI Search
Shaping content so AI search engines use it and cite it in the answers they write.
Google AI ModeAI Search
A conversational mode of Google Search that answers with a generated response and links, rather than a page of results.
H
HreflangSEO Fundamentals
An annotation listing the language and regional versions of a page, so each searcher sees the right one.
I
IndexabilitySEO Fundamentals
Whether a page is eligible to be indexed at all. Being indexable is a requirement, not a promise.
Interaction to Next PaintSEO Fundamentals
How quickly a page responds to clicks, taps and key presses. Good is 200 milliseconds or less.
J
JavaScript SEOSEO Fundamentals
Making sure pages that rely on JavaScript can still be crawled, rendered and indexed.
K
Knowledge GraphAI Search
Google's store of entities and the relationships between them, the thing behind knowledge panels.
Knowledge PanelSEO Fundamentals
Google's information box about an entity, generated automatically from the Knowledge Graph.
L
Large Language ModelAI Search
A model trained on broad data to predict text, which is what sits underneath ChatGPT, Claude and Gemini.
Largest Contentful PaintSEO Fundamentals
How long the biggest image, text block or video in view takes to render. Good is 2.5 seconds or less.
LLMOAI Search
Improving how large language models such as ChatGPT, Claude and Gemini describe and cite your brand.
R
Referring DomainsSEO Fundamentals
The websites that link to yours, each counted once. Every tool counts them differently.
Robots.txtSEO Fundamentals
A file at the root of a site telling crawlers which URLs they may request. It controls crawling, not indexing.
S
Schema MarkupSEO Fundamentals
Code that labels what a page is about, so machines can read it without guessing.
Semantic SearchAI Search
Retrieval that matches the meaning of a query rather than its literal words.
SERPSEO Fundamentals
The page a search engine shows after a search: organic results, ads, AI Overviews and other features.
T
Title TagSEO Fundamentals
The HTML title element that names a page. Google's main source for the search result title, but not its only one.
Training DataAI Search
The text a model learns from before it answers anything, including a large amount of the public web.
V
Voice SearchSEO Fundamentals
Searching by speaking instead of typing. A different input method, not a different index.
X
XML SitemapSEO Fundamentals
A file listing the URLs you want crawled, with optional metadata. A discovery aid, not a ranking one.
Y
YMYLSEO Fundamentals
Google's term for topics where bad information could harm health, finances, safety or society.
Z
Zero-Click SearchAI Search
A search that ends without a click to any website, because the answer or next step is on the results page.
No term matches that yet. The glossary is growing a few terms at a time.
Want the long version?
These definitions are the short answer. For the method behind them, start with What Is AI SEO?, then Query Fan-Out and How AI Overviews Impact SEO. Every guide is in the SEO and AI Search Guides library.