Every term, defined once

74 terms from search, AI and the machinery underneath both, each defined in a single sentence that does not send you to another definition. Written for someone who has never had to know any of this.

A B C D E F G H I J K L M NPR S T U VZ

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301 redirectSearch: A 301 redirect permanently sends anyone visiting an old address to a new one, including machines.

A

AEOAI search: AEO, or answer engine optimization, is the work of getting your page used as the source of a direct answer, such as the box at the top of a results page, rather than as one link among ten.
AgentAI: An agent is an AI tool that can take actions, such as browsing pages or filling a form, rather than only writing an answer.
AI crawlerAI search: An AI crawler is the specific automated visitor an AI search company sends to read your pages, such as GPTBot, ClaudeBot or PerplexityBot.
AI ModeAI search: AI Mode is Google's fully conversational search experience, where the whole result is an answer you can ask follow-up questions of.
AI OverviewsAI search: AI Overviews are the AI-written answers Google places above its normal list of links.
AI searchAI: AI search is a program you ask questions in plain language, like ChatGPT, Claude, Gemini or Perplexity, which writes you an answer instead of handing you a list of links.
Alt textTechnical: Alt text is a written description of an image, held in the page's code for people who cannot see the image and for machines that cannot interpret it.
Anchor textSearch: Anchor text is the visible, clickable words of a link.
Answer engineAI search: An answer engine is any search product that responds with a direct answer instead of a list of links.

B

BacklinkSearch: A backlink is a link to your site from somebody else's.
BaselineMeasurement: A baseline is the measurement you take before making changes, so later numbers have something to be compared against.
Branded promptAI search: A branded prompt is a question that contains your company name, such as asking AI search what your business does.

C

CanonicalSearch: A canonical tag tells a search engine which version of a page is the real one when several addresses show the same content.
CDNTechnical: A CDN is a network of servers around the world that keeps copies of your site so visitors are served from somewhere close to them.
CitationAI search: A citation is a link or source name AI search shows next to its answer to indicate where a piece of information came from.
Click-through rateSearch: Click-through rate is the share of the people shown your link who actually clicked it.
Client-side renderingTechnical: Client-side rendering means the page arrives nearly empty and its content is built by code running in the visitor's browser.
Confidence intervalMeasurement: A confidence interval is the range a measured number is probably within, given how many times you measured.
Context windowAI: A context window is the maximum amount of text AI search can hold in mind at once, counted in tokens.
Control groupMeasurement: A control group is a comparable set you leave alone, so you can tell whether a change caused a result or everything moved anyway.
Core Web VitalsSearch: Core Web Vitals are Google's three measurements of how fast and stable a page feels to a real person.
CrawlerTechnical: A crawler is a program that visits web pages on its own and copies what it finds, so a search engine or AI search can use the contents later.

D

DNSTechnical: DNS is the system that turns a domain name into the address of the machine that answers for it.
Duplicate contentSearch: Duplicate content is the same or nearly the same text appearing at more than one address.

E

E-E-A-TSearch: E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness, the qualities Google says its raters look for.
EdgeTechnical: The edge is the layer that sits in front of your website and answers requests before they reach your own server.
EmbeddingAI: An embedding is a way of turning a piece of text into a list of numbers so a machine can judge which texts are about similar things.
EntitySearch: An entity is a specific thing in the world that a machine has decided it knows about: a company, a person, a place.

F

Featured snippetSearch: A featured snippet is the short answer Google lifts from a page and shows in a box at the top of the results.
Fine-tuningAI: Fine-tuning is further training of an existing model on a narrower set of examples to change how it behaves.

G

Generative engineAI: A generative engine is software that writes a new answer to your question rather than retrieving an existing page for you to read.
GEOAI search: GEO, or generative engine optimization, is the work of making it more likely that AI search names your business when someone asks it a question about what you sell.
GroundingAI: Grounding is tying an answer to real fetched sources rather than letting the model answer from memory.

H

HallucinationAI: A hallucination is AI search stating something false with the same confidence it states something true.
hreflangSearch: hreflang is markup telling search engines which language and country each version of a page is meant for.
HTTP status codeTechnical: An HTTP status code is the three-digit number a server returns with every page, saying whether the request worked.
HydrationTechnical: Hydration is the step where a page that arrived as plain text has its interactive behaviour attached by code.

I

ImpressionsSearch: An impression is one instance of your link being shown to somebody, whether or not they clicked it.
IndexSearch: The index is the searchable copy of the web a search engine keeps. If a page is not in it, that page cannot appear in results.
InferenceAI: Inference is the act of running a model to produce an answer, as opposed to training it in the first place.
Internal linkSearch: An internal link is a link from one page of your site to another page of your site.

J

JSON-LDTechnical: JSON-LD is the format structured data is usually written in: a block of machine-readable facts placed in the page's code.

K

Knowledge cutoffAI: A knowledge cutoff is the date after which a model learned nothing during training.

L

LCPSearch: LCP, or largest contentful paint, measures how long it takes for the biggest thing on screen to appear.
LLMAI: An LLM, or large language model, is the program underneath AI search: software trained on an enormous amount of text that predicts what words should come next.
llms.txtTechnical: llms.txt is an optional plain text file at the top level of a website that tells AI search, in ordinary language, what the site is and which pages matter most.

M

Mention rateMeasurement: Mention rate is the share of answers that named your business, out of all the times a question was asked.
Meta descriptionTechnical: A meta description is the short summary of a page written into its code, often shown underneath the link in search results.

N

noindexSearch: noindex is an instruction in a page's code telling search engines not to include it in results.

P

People Also AskSearch: People Also Ask is the expandable list of related questions Google shows inside its results.
PromptAI: A prompt is whatever you type to AI search: the question, the instruction, or both.
Prompt setAI search: A prompt set is the fixed list of buying questions you measure yourself against, asked the same way every time.

R

RAGAI: RAG, or retrieval-augmented generation, is the standard way AI search answers a question about the live web: search first, read the results, then write the answer using them.
RenderingTechnical: Rendering is the step where a browser runs a page's code to build what you finally see on screen.
RetrievalAI: Retrieval is the step where AI search fetches live web pages in the middle of answering you, instead of relying only on what it already knows.
robots.txtTechnical: robots.txt is a plain text file at the top level of a website that lists which automated visitors are allowed in and which are not.

S

SamplingMeasurement: Sampling means asking the same question several times instead of once, because AI search does not give an identical answer every time.
Schema.orgTechnical: Schema.org is the shared vocabulary that structured data uses, defining what counts as a product, an organisation, an article and so on.
Search ConsoleSearch: Search Console is Google's free tool showing how your site performs in its search results, including which queries showed your pages.
SEOSearch: SEO, or search engine optimization, is the work of getting a page of your website to appear high in a list of search results.
SERPSearch: A SERP is a search engine results page: everything Google shows you after you type a query.
Server-side renderingTechnical: Server-side rendering means the page arrives from the server with its text already in it.
Share of voiceAI search: Share of voice is how often your business is named compared with your competitors across the same set of questions.
SitemapSearch: A sitemap is a file listing the pages on your site that you want machines to know about.
Statistical significanceMeasurement: Statistical significance is the judgement that a difference is larger than what random variation alone would likely produce.
Structured dataTechnical: Structured data is information written into a page in a fixed format that states plainly what the page is: that this is a product, that this is its price, that this is the business selling it.
System promptAI: A system prompt is a hidden instruction the company running AI search gives it before you ever type anything.

T

TokenAI: A token is a chunk of text, usually a word or part of a word, and it is the unit AI search actually reads and counts.
Topical authoritySearch: Topical authority is the degree to which a site is seen as covering a subject completely rather than mentioning it once.
Training dataAI: Training data is the enormous body of text AI search learned from before it was released, which is fixed, often months or years old, and cannot be edited by you.

U

User agentTechnical: A user agent is the name a visitor gives when it arrives at your site, which is how you can tell a browser from a crawler.

V

VarianceMeasurement: Variance is how much a result moves around when you repeat the same test.

Z

Zero-click searchAI search: A zero-click search is one where the person gets what they needed without visiting any website.