SEO Glossary: 137 SEO, AI Search and International SEO Terms

This SEO glossary explains 137 terms I use every day with clients, in plain English. It covers SEO basics, technical and on-page SEO, local SEO, and two areas most glossaries skip: international SEO (hreflang, x-default, ccTLDs) and AI search (AI Overviews, GEO, query fan-out). Each entry says what the term means and why it matters for your business. There’s also a list of outdated SEO terms you can ignore.

SEO field guide · Updated October 2026

SEO Glossary

137 search terms in plain English, grouped the way you'd learn them, from crawling and canonical tags to hreflang and AI Overviews. Every entry tells you what the term means, why it matters to your business, and where to go next.

Popular: Hreflang Canonical tag AI Overviews Core Web Vitals E-E-A-T

Written by Jagriti Lakher, international SEO consultant

SEO Basics

Start here if you're new to search. 25 terms

SEO (search engine optimization)

BeginnerSEO Basics

Improving a website so it appears higher in unpaid search results for the searches your customers make.

Why it matters: Organic traffic keeps coming without paying for every click.

BeginnerSEO Basics

Unpaid results in a search engine, as opposed to ads.

Why it matters: Organic rankings build lasting visibility; ads stop when the budget stops.

Search algorithm

BeginnerSEO Basics

The systems a search engine uses to decide which pages to show and in what order.

Why it matters: You can't control the algorithm, but you can control how useful, clear and trustworthy your pages are.

Core update

IntermediateSEO Basics

A broad change Google makes to its ranking systems several times a year. Rankings can rise or fall across many sites at once.

Why it matters: After an update, judge the trend over several weeks rather than reacting to one day's data.

Keyword difficulty

IntermediateSEO Basics

A score from SEO tools estimating how hard a keyword is to rank for, mostly based on the links pointing to the pages already ranking.

Why it matters: It's each tool's estimate, not a Google metric, so use it as a rough guide.

Search intent

BeginnerSEO Basics

The reason behind a search: to learn something, compare options, find a specific site or buy.

Why it matters: A page that doesn't match the intent rarely ranks, however well it's written.

Example: "what is hreflang" wants an explanation; "hreflang consultant" wants someone to hire.

BeginnerSEO Basics

A search where the person gets their answer on the results page, from a snippet or AI answer, without clicking any result.

Why it matters: Impressions can grow while clicks stay flat, so track visibility as well as traffic.

BeginnerSEO Basics

A short answer Google shows near the top of the results, taken from one web page.

Why it matters: Clear, direct answers under question-style headings have a better chance of being chosen.

Manual action

IntermediateSEO Basics

A penalty applied by a Google reviewer when a site breaks the spam policies. It appears in Search Console under Security & Manual Actions.

Why it matters: It can remove pages from results until you fix the issue and request a review.

YMYL (Your Money or Your Life)

IntermediateSEO Basics

Topics that could affect someone's health, finances, safety or rights, such as legal, medical or financial advice.

Why it matters: Google holds these pages to a higher standard of trust and expertise.

SERP features

BeginnerSEO Basics

Anything on a results page beyond the standard blue links, such as AI Overviews, featured snippets, People Also Ask, map packs, videos, images and sitelinks.

Why it matters: They decide how much attention the normal results get, so check them before choosing a target keyword.

BeginnerSEO Basics

Extra links Google shows under a result, usually for brand searches, pointing to important pages on that site.

Why it matters: You can't set them directly, but clear site structure and internal links help Google choose good ones.

Google Discover

BeginnerSEO Basics

A personalised feed of articles in the Google app and on mobile, shown based on interests rather than searches.

Why it matters: Fresh, helpful content with large, high-quality images can earn extra traffic from it.

Topical authority

IntermediateSEO Basics

How completely and reliably a site covers a subject, built through many connected, in-depth pages on that topic.

Why it matters: Sites that cover a topic thoroughly tend to rank more easily for new pages on it.

SEO audit

BeginnerSEO Basics

A structured review of a site's technical health, content, links and rankings that ends in a prioritised list of fixes.

Why it matters: It shows what's actually holding rankings back before you spend on new content.

Technical SEO

How search engines crawl, index and load your site. 29 terms

Technical SEO

BeginnerTechnical SEO

Making a site easy for search engines to crawl, index, render and load: speed, mobile usability, sitemaps, redirects, canonical tags and structured data.

Why it matters: If Google can't crawl or index a page, nothing else you do on it matters.

Rendering

AdvancedTechnical SEO

When a search engine runs a page's code, including JavaScript, to see the final content a visitor sees.

Why it matters: Content that only appears after JavaScript runs may be missed or delayed, and many AI crawlers don't run JavaScript at all.

Crawl budget

AdvancedTechnical SEO

How many pages a search engine is willing to crawl on your site in a given time. It mostly matters for very large sites.

Why it matters: For small sites, fixing broken and duplicate pages matters more.

XML sitemap

BeginnerTechnical SEO

A file listing the pages you want search engines to find, usually at /sitemap_index.xml on WordPress sites using Rank Math.

Why it matters: It helps new and updated pages get found faster.

Robots.txt

IntermediateTechnical SEO

A file at the root of your site that tells crawlers which areas they may or may not visit.

Why it matters: One wrong line can block search engines or AI crawlers from your whole site.

Disallow: /wp-admin/ blocks the WordPress admin area but leaves your pages open.

HTTP status codes

IntermediateTechnical SEO

Three-digit codes a server returns for each request: 200 means OK, 301 a permanent redirect, 302 a temporary redirect, 404 not found, 410 permanently gone, and 5xx a server error.

Why it matters: Wrong codes can keep pages out of search or waste link value.

Redirect chain

AdvancedTechnical SEO

When one URL redirects to another that redirects again before reaching the final page.

Why it matters: Chains slow pages down and can lose link value. Point every redirect straight to the final URL.

Soft 404

AdvancedTechnical SEO

A page that tells visitors it doesn't exist (or is nearly empty) but returns a 200 OK code.

Why it matters: Search Console flags these. Return a real 404 or 410, or add proper content.

Site architecture

IntermediateTechnical SEO

How pages are organised and linked, from the homepage down to individual posts.

Why it matters: Important pages should be reachable within about three clicks of the homepage.

Mobile-first indexing

BeginnerTechnical SEO

Google uses the mobile version of your pages to index and rank them.

Why it matters: If content is missing or broken on mobile, it effectively doesn't exist for Google.

Core Web Vitals

IntermediateTechnical SEO

Google's page-experience measures: loading (LCP), responsiveness (INP) and visual stability (CLS). Good scores are LCP within 2.5 seconds, INP within 200 milliseconds and CLS of 0.1 or less.

Why it matters: Slow, jumpy pages lose visitors before they read anything.

Lazy loading

IntermediateTechnical SEO

Loading images or other content only when a visitor scrolls near them.

Why it matters: It speeds up pages, but don't lazy-load the main image at the top of the page.

HTTPS

BeginnerTechnical SEO

The secure version of HTTP, shown by the padlock in the browser.

Why it matters: Browsers warn visitors about non-secure pages, and Google uses HTTPS as a light ranking signal.

Schema markup (structured data)

IntermediateTechnical SEO

Code that describes a page's content in a standard format, such as Article, Person, Organization or LocalBusiness.

Why it matters: It helps search engines and AI tools understand who you are and what each page is.

Rich results

IntermediateTechnical SEO

Search results with extra features, such as review stars, images or breadcrumbs, often powered by schema markup. Google changes which types it shows; FAQ rich results, for example, are no longer shown.

Why it matters: Rich results can stand out, but schema doesn't guarantee them.

Log file analysis

AdvancedTechnical SEO

Reviewing your server's records of which pages search engine bots actually visited.

Why it matters: It shows what Google is really crawling, not just what you hope it crawls.

Googlebot

BeginnerTechnical SEO

Google's web crawler. Each crawler identifies itself with a user-agent name, such as Googlebot or Bingbot, which robots.txt rules can target.

Why it matters: Blocking or slowing Googlebot by mistake can drop pages out of search.

JavaScript SEO

AdvancedTechnical SEO

Making sure content and links that rely on JavaScript can still be crawled, rendered and indexed.

Why it matters: Key text and links should be in the HTML where possible, because rendering is slower and some crawlers skip it.

Server-side rendering (SSR)

AdvancedTechnical SEO

Building a page's HTML on the server, so crawlers and visitors receive the full content without running JavaScript first.

Why it matters: It makes content easier for search engines and AI crawlers to read.

Faceted navigation

AdvancedTechnical SEO

Filters on category pages, such as size, colour or price, that can create thousands of URL combinations.

Why it matters: Uncontrolled filter URLs waste crawling and create duplicates; keep only useful combinations indexable.

Pagination

IntermediateTechnical SEO

Splitting a long list, such as blog archives or products, across several pages (page 2, page 3 and so on).

Why it matters: Each page should have its own URL and normal links so search engines can reach everything.

On-Page & Content

What's on each page, and how it's written. 23 terms

On-page SEO

BeginnerOn-Page & Content

Optimizing what's on each page: the title tag, headings, content, internal links, images and meta description.

Why it matters: It tells search engines and visitors what the page is about.

Title tag

BeginnerOn-Page & Content

The page title shown as the clickable headline in search results. Around 50–60 characters usually displays in full.

Why it matters: It's one of the clearest signals of what the page is about, and it decides whether people click.

Meta description

BeginnerOn-Page & Content

The short summary that may appear under your title in search results. About 140–160 characters usually fits.

Why it matters: It doesn't directly affect rankings, but a clear one improves clicks.

SEO-friendly URL (slug)

BeginnerOn-Page & Content

A short, readable web address that describes the page, using hyphens between words.

Why it matters: Clean URLs are easier to read, share and understand.

Example: /resources/checklist/international-seo-checklist/ instead of /?p=1234.

Header tags (H1–H6)

BeginnerOn-Page & Content

HTML headings that structure a page. Most pages should have one H1, with H2s and H3s for sections.

Why it matters: Clear headings help readers, search engines and AI tools follow your content.

Anchor text

BeginnerOn-Page & Content

The clickable words in a link.

Why it matters: Descriptive anchor text tells search engines what the linked page is about.

Example: "international SEO checklist" is better anchor text than "click here".

Alt text

BeginnerOn-Page & Content

A short text description of an image, read by screen readers and search engines.

Why it matters: It makes images accessible and helps them appear in image search.

Keyword cannibalization

IntermediateOn-Page & Content

When two or more of your pages target the same search, so they compete with each other.

Why it matters: It can keep both pages lower than one strong page would rank.

Entity

AdvancedOn-Page & Content

A clearly defined thing search engines recognise, such as a person, business, place or concept, and its relationships to other entities.

Why it matters: Consistent details about you across the web help search engines and AI tools recognise your business.

IntermediateOn-Page & Content

Search that understands meaning and context, not just exact keyword matches.

Why it matters: Cover a topic thoroughly in natural language instead of repeating one phrase.

E-E-A-T

IntermediateOn-Page & Content

Experience, Expertise, Authoritativeness and Trustworthiness: the qualities Google's quality guidelines use to judge content. Trust matters most.

Why it matters: Real author details, first-hand proof and accurate claims make content more trustworthy.

Helpful content

IntermediateOn-Page & Content

Content made mainly to help people rather than to rank. Google's helpful-content signals became part of its core ranking systems in 2024.

Why it matters: Pages written only for search engines tend to lose rankings over time.

Thin content

BeginnerOn-Page & Content

Pages with little useful content, such as near-empty pages or short pages repeated with minor changes.

Why it matters: Many thin pages can make your whole site look lower quality.

Content refresh

BeginnerOn-Page & Content

Updating an existing page with new information, examples and data instead of writing a new one.

Why it matters: Refreshed pages often regain rankings faster than new pages can earn them.

Passage ranking

AdvancedOn-Page & Content

Google's ability to rank a specific section of a long page for a narrow question, even if the whole page is about a broader topic.

Why it matters: Clear headings and self-contained sections give each part of a page its own chance to rank and be cited.

Open Graph tags

BeginnerOn-Page & Content

Meta tags that control the title, description and image shown when a page is shared on LinkedIn, Facebook, WhatsApp and similar apps.

Why it matters: A good preview image and title get more clicks when people share your pages.

Off-Page & Local

Links, mentions, reviews and your Google listing. 13 terms

Referring domains

IntermediateOff-Page & Local

The number of different websites linking to you. Ten links from one site count as one referring domain.

Why it matters: Links from many different relevant sites matter more than many links from one.

IntermediateOff-Page & Local

Link attributes that tell search engines not to pass ranking credit: rel="nofollow", rel="sponsored" for paid links and rel="ugc" for user-generated content. Google treats them as hints.

Why it matters: Paid links must be marked sponsored to stay within Google's guidelines.

Unlinked brand mention

BeginnerOff-Page & Local

When a website mentions your business without linking to it.

Why it matters: Mentions build recognition with search engines and AI tools, and are easy wins to turn into links.

Google Business Profile

BeginnerOff-Page & Local

Your free business listing on Google Search and Maps, with your address or service area, hours, reviews and posts.

Why it matters: It's essential for appearing in local and map results.

Local pack (map pack)

BeginnerOff-Page & Local

The map and list of usually three local businesses Google shows for searches with local intent.

Why it matters: Reviews, relevance and distance decide who appears there.

NAP consistency

BeginnerOff-Page & Local

Keeping your business Name, Address and Phone number identical everywhere online.

Why it matters: Matching details help search engines trust your business information.

Local citations

BeginnerOff-Page & Local

Mentions of your business details on directories and other websites.

Why it matters: They support your Google Business Profile and help people find you.

International SEO

Ranking in more than one country or language. 17 terms

Hreflang in 30 seconds

A page available in three English versions should list all three plus a fallback, on every version, including itself:

<link rel="alternate" hreflang="en-gb" href="https://example.com/uk/" /> <link rel="alternate" hreflang="en-au" href="https://example.com/au/" /> <link rel="alternate" hreflang="en-us" href="https://example.com/us/" /> <link rel="alternate" hreflang="x-default" href="https://example.com/" />

Common mistakes: en-UK instead of en-GB · missing return tags · pointing hreflang at redirected or noindexed URLs.

International SEO

BeginnerInternational SEO

Optimizing a website to rank in more than one country or language, using country-specific keyword research, the right URL structure, hreflang tags, localized content and links from each market.

Why it matters: Without it, your site may rank at home but stay invisible to buyers abroad.

Language and region codes

AdvancedInternational SEO

Hreflang uses an ISO 639-1 language code, optionally followed by an ISO 3166-1 alpha-2 country code.

Why it matters: Invalid codes are ignored. The UK is "gb", so use en-GB, not en-UK.

en, en-GB, en-AU, ar-AE

Self-referencing hreflang

AdvancedInternational SEO

Each page's hreflang set includes a tag pointing to the page itself, as well as to its alternates.

Why it matters: Leaving it out is one of the most common hreflang mistakes.

x-default

AdvancedInternational SEO

A hreflang value naming the fallback page shown when no language or country version matches the searcher, often a country-selector page.

Why it matters: It stops visitors from unlisted countries landing on the wrong version.

<link rel="alternate" hreflang="x-default" href="https://example.com/" />

Subfolder vs subdomain

IntermediateInternational SEO

Two ways to organise country versions on one domain: subfolders (example.com/au/) or subdomains (au.example.com).

Why it matters: Subfolders are often the simplest for a growing business because all versions share one domain's authority.

Geotargeting

IntermediateInternational SEO

Signalling which country a page or section is meant for, through the URL structure, hreflang, local content and links. Search Console's old country-targeting setting was retired in 2022.

Why it matters: Country signals now come from your site itself, not a setting.

IP-based redirects

IntermediateInternational SEO

Automatically sending visitors to a country version based on their IP address.

Why it matters: They can stop search engines and travellers seeing your other versions. A visible country switcher is safer.

Country selector

IntermediateInternational SEO

A visible menu or banner that lets visitors choose their country or language version.

Why it matters: It respects visitor choice and keeps every version crawlable when built with normal links.

Multilingual vs multiregional site

IntermediateInternational SEO

A multilingual site offers several languages; a multiregional site targets several countries, which can share a language (for example the US, UK and Australia).

Why it matters: Each needs a different setup for URLs and hreflang.

Transcreation

IntermediateInternational SEO

Recreating marketing copy for another market so the message, tone and offer land the same way, rather than translating word for word.

Why it matters: Headlines, calls to action and slogans usually need transcreation, not translation.

Regional search engines

IntermediateInternational SEO

Search engines that lead in particular countries, such as Baidu in China, Naver in South Korea, Yandex in Russia and Seznam in the Czech Republic.

Why it matters: If you target those markets, Google-only optimisation isn't enough.

AI Search

Being found and cited in AI answers. 14 terms

AI Mode

BeginnerAI Search

Google's conversational search mode, where people ask follow-up questions and get AI-written answers with links.

Why it matters: Clear, well-structured pages are easier for it to use and cite.

LLM (large language model)

BeginnerAI Search

The type of AI behind tools such as ChatGPT, Gemini, Claude and Copilot, trained on large amounts of text to understand and write language.

Why it matters: LLM-powered answers are now a second search channel alongside Google's blue links.

GEO (generative engine optimization)

IntermediateAI Search

Optimizing content so AI tools such as ChatGPT, Google AI Overviews and Copilot can understand, trust and cite it.

Why it matters: More buyers now start their research with an AI assistant.

AEO (answer engine optimization)

IntermediateAI Search

Structuring content as clear questions with short, direct answers that search features and AI tools can lift as an answer.

Why it matters: It overlaps heavily with GEO and good on-page SEO.

Query fan-out

AdvancedAI Search

When an AI search tool splits one question into several related searches, then combines the results into one answer.

Why it matters: Covering the related sub-questions on your page gives it more chances to be used.

AI visibility (share of voice)

IntermediateAI Search

How often your brand is mentioned or cited in AI answers for your topics, compared with competitors.

Why it matters: It's the AI-search equivalent of rankings, so track it over time.

AI crawlers

IntermediateAI Search

Bots AI companies use to read websites, such as OAI-SearchBot and GPTBot (OpenAI), ClaudeBot (Anthropic) and PerplexityBot. You can allow or block them in robots.txt.

Why it matters: Blocking search-related AI crawlers can keep you out of AI answers.

llms.txt

IntermediateAI Search

A proposed text file at the root of a site that summarises its key pages for AI tools. Google has said it doesn't use it for Search.

Why it matters: It's optional and low effort; it doesn't replace good content or SEO.

IntermediateAI Search

AI tools that do more than answer: they browse, compare options and complete tasks, such as booking or shortlisting, on the user's behalf.

Why it matters: Clear prices, services, contact details and booking paths make it easier for AI agents to choose you.

Prompt tracking

IntermediateAI Search

Regularly running the questions your buyers ask in ChatGPT, Google AI Mode, Copilot and Perplexity, and recording which brands are mentioned or cited.

Why it matters: It's how you measure AI visibility, because AI answers change from run to run.

Spam & Penalties

Tactics Google penalises, so you can spot them in a proposal. 7 terms

Doorway pages

IntermediateSpam & Penalties

Many similar pages created to rank for slightly different searches, such as one near-identical page per city, that all funnel visitors to the same place.

Why it matters: Google treats them as spam; location pages need genuinely local content.

Site reputation abuse

AdvancedSpam & Penalties

Third-party pages published on a trusted site mainly to borrow its rankings, sometimes called parasite SEO. A Google spam policy since 2024.

Why it matters: Buying placements on big sites to rank for unrelated topics can get those pages removed.

Expired domain abuse

AdvancedSpam & Penalties

Buying an expired domain with existing links and filling it with low-value content to exploit its past reputation. A Google spam policy since March 2024.

Why it matters: Old links don't carry over when the new site has nothing to do with the old one.

Negative SEO

IntermediateSpam & Penalties

Attempts to harm a competitor's rankings, such as pointing spammy links at their site.

Why it matters: Google says it ignores most spammy links, so most sites don't need to react unless a manual action appears.

Measurement

Tracking what's working. 9 terms

Google Search Console

BeginnerMeasurement

Google's free tool showing how your site performs in Search: clicks, impressions, average position, indexing and errors.

Why it matters: It's the most accurate source of your Google search data.

Average position

BeginnerMeasurement

Your page's average ranking for the searches it appeared in, where 1 is the top result.

Why it matters: Track it per keyword and per country, not just as one site-wide number.

Organic CTR

BeginnerMeasurement

The share of people who click your result after seeing it: clicks divided by impressions.

Why it matters: A low CTR on a well-ranked page usually means the title or description needs work.

IndexNow

IntermediateMeasurement

A way to tell Bing and other participating search engines instantly when you publish or update a page. Google doesn't use it.

Why it matters: It helps new pages appear faster in Bing-powered results.

Outdated SEO terms

Still listed as current in many glossaries. If you see one in an SEO proposal, ask what the person means.

ThenNow
Google My Business
Google Business Profile

Renamed Google Business Profile in 2021.

E-A-T
E-E-A-T

Google added Experience in 2022, making it E-E-A-T.

FID (First Input Delay)
Core Web Vitals (INP)

Replaced by INP as a Core Web Vital in March 2024.

Meta keywords tag
Title tag and on-page content

Google has ignored it for ranking since 2009.

Keyword density
Search intent and topic coverage

Not a ranking factor; repeating a keyword to hit a percentage reads badly and can count as keyword stuffing.

LSI keywords
Semantic search and entities

Google has said it doesn't use "LSI keywords"; covering related subtopics naturally is what helps.

Webmaster Guidelines
Google Search Essentials

Replaced by Google Search Essentials in 2022.

Mobile-Friendly Test
Lighthouse or PageSpeed Insights

Retired by Google in December 2023.

International Targeting report
Geotargeting through URLs, hreflang and content

Search Console's country-targeting setting was retired in 2022.

FAQ rich results
Clear question-and-answer sections for readers and AI tools

Google no longer shows them in Search.

SGE (Search Generative Experience)
AI Overviews

Google's AI search test was launched to everyone as AI Overviews in May 2024.

Bing Chat
Microsoft Copilot

Renamed Microsoft Copilot in late 2023.

Google Bard
Gemini

Renamed Gemini in February 2024.

Know the terms. Now put them to work.

I help businesses in the UAE, Australia, the US, Canada and the UK with SEO, international SEO and AI search visibility.