46 terms defined — free reference

SEO Glossary

Every SEO term you need to know, defined clearly with why it matters and how to fix it. Covers technical SEO, on-page, off-page, Core Web Vitals, AI search optimization, and analytics.

Technical SEO On-Page SEO Off-Page SEO AI & GEO Core Web Vitals Analytics & Metrics

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Technical SEO

Crawl Budget

Crawl budget is the number of pages a search engine will crawl on your site within a given timeframe, determined by crawl rate limit (how fast Googlebot can crawl without overloading your server) and crawl demand (how much Google wants to crawl based on popularity and freshness).

Canonical Tag

A canonical tag (rel="canonical") is an HTML element that tells search engines which version of a page is the preferred, authoritative copy when multiple URLs serve similar or identical content. It prevents duplicate content issues by consolidating ranking signals to one URL.

Robots.txt

Robots.txt is a text file at the root of a website (example.com/robots.txt) that tells search engine and AI crawlers which pages and directories they are allowed or disallowed from accessing. It uses User-Agent directives to control access per crawler.

Redirect Chain

A redirect chain occurs when a URL redirects to another URL, which then redirects to yet another URL, creating a series of sequential hops (e.g., Page A → 301 → Page B → 301 → Page C). Each hop adds latency and dilutes the link equity passed to the final destination.

301 Redirect

A 301 redirect is a permanent server-side redirect that tells search engines a page has permanently moved to a new URL. It passes approximately 90-99% of the original page's link equity (PageRank) to the new URL and instructs search engines to update their index.

XML Sitemap

An XML sitemap is a file (typically at /sitemap.xml) that lists all the important URLs on your website along with metadata like last modification date, change frequency, and priority. It helps search engines discover and crawl your pages more efficiently.

Noindex

Noindex is a robots meta tag directive (meta name="robots" content="noindex") that tells search engines not to include a specific page in their search index. The page can still be crawled, but it will not appear in search results.

Indexation

Indexation is the process by which search engines add web pages to their searchable database (index). A page must be crawled, rendered, and evaluated before it can be indexed. Only indexed pages can appear in search results.

Hreflang

Hreflang is an HTML attribute (rel="alternate" hreflang="x") that tells search engines which language and regional version of a page to serve to users in different locations. It links together translated or localized versions of the same content.

Orphan Page

An orphan page is a page on your website that has no internal links pointing to it from any other page. It exists in your sitemap or can be accessed directly via URL, but no other page on your site links to it.

Structured Data

Structured data is code (typically JSON-LD format) added to web pages that helps search engines understand the content in a machine-readable way. It uses the Schema.org vocabulary to describe entities like articles, products, FAQs, events, and organizations, enabling rich results in search.

Schema Markup

Schema markup is a standardized vocabulary (developed by Schema.org and supported by Google, Bing, Yahoo, and Yandex) used to annotate web content with structured data. Common schema types include Article, Product, FAQPage, HowTo, LocalBusiness, Organization, BreadcrumbList, and Review.

HTTPS

HTTPS (Hypertext Transfer Protocol Secure) is the encrypted version of HTTP that uses SSL/TLS certificates to secure data transmitted between a user's browser and the web server. Google has confirmed HTTPS as a ranking signal since 2014.

Duplicate Content

Duplicate content is substantively similar or identical content that appears on multiple URLs, either within the same website (internal duplicates) or across different websites (external duplicates). Search engines must decide which version to index and rank.

Internal Linking

Internal linking is the practice of connecting pages within your website using hyperlinks. Internal links distribute link equity (PageRank) across your site, help search engines understand your site structure and content hierarchy, and guide users to related content.

Title Tag

A title tag is an HTML element (<title>) that specifies the title of a web page. It appears in browser tabs, search engine results pages (SERPs) as the clickable headline, and social media shares. It is the single most important on-page SEO element.

Meta Description

A meta description is an HTML meta tag that provides a brief summary of a web page's content. It appears below the title tag in search engine results and is typically 150-160 characters long. Google has confirmed meta descriptions are not a direct ranking factor.

H1 Tag

An H1 tag is the primary heading element on a web page, indicating the main topic of the page's content. Best practice is one H1 per page, containing the primary keyword, with subsequent headings (H2, H3) creating a logical content hierarchy.

Alt Text (Alternative Text)

Alt text (alternative text) is an HTML attribute added to image tags that describes the content and function of an image. It serves as a text alternative when images can't be displayed, is read by screen readers for accessibility, and helps search engines understand image content.

E-E-A-T

E-E-A-T stands for Experience, Expertise, Authoritativeness, and Trustworthiness. It is a framework from Google's Search Quality Rater Guidelines used to evaluate the quality of web content. While not a direct ranking algorithm, it influences how Google's algorithms assess content quality.

Keyword Cannibalization

Keyword cannibalization occurs when multiple pages on the same website target the same keyword or search intent, forcing them to compete against each other in search results. Instead of one strong page ranking, Google must choose between multiple weaker options.

Content Structure

Content structure refers to how information is organized on a web page using headings (H1-H6), paragraphs, lists, tables, and other formatting elements. Well-structured content uses a clear hierarchy, front-loads important information, and creates self-contained sections that can be extracted by AI engines.

Image Optimization

Image optimization is the process of reducing image file sizes and improving delivery without sacrificing visual quality. It includes compression, format selection (WebP, AVIF), responsive sizing, lazy loading, and descriptive alt text. Optimized images load faster and consume less bandwidth.

Backlink

A backlink (also called an inbound link or incoming link) is a hyperlink from one website to another. Backlinks are one of Google's most important ranking signals because they act as votes of confidence from other websites, indicating that your content is valuable and trustworthy.

Domain Authority

Domain Authority (DA) is a metric developed by Moz that predicts how likely a website is to rank in search results, scored on a scale of 1-100. Ahrefs has a similar metric called Domain Rating (DR). Neither is a Google ranking factor, but both correlate with ranking ability.

Link Equity

Link equity (also called link juice or PageRank) is the ranking value passed from one page to another through hyperlinks. When a high-authority page links to another page, it passes a portion of its authority through that link, boosting the linked page's ranking potential.

Referring Domain

A referring domain is a unique website that contains at least one backlink pointing to your site. One referring domain can provide multiple backlinks, but the diversity of referring domains is more important than the total number of individual links.

Anchor Text

Anchor text is the visible, clickable text of a hyperlink. Search engines use anchor text as a signal to understand what the linked page is about. Natural anchor text profiles include a mix of branded, exact-match, partial-match, and generic text.

GEO (Generative Engine Optimization)

Generative Engine Optimization (GEO) is the practice of optimizing content to get cited by AI-powered search engines like ChatGPT, Claude, Perplexity, and Google AI Overviews. The term was formalized by Princeton researchers who found specific content strategies can boost AI visibility by up to 40%.

AEO (Answer Engine Optimization)

Answer Engine Optimization (AEO) is the practice of optimizing content specifically for AI-powered search features like Google AI Overviews, Bing's AI chat, and featured snippets. AEO focuses on providing direct, structured answers that AI can extract and display.

LLM Seeding

LLM seeding is the practice of creating and distributing content across the web in a way that trains large language models (LLMs) to associate your brand with specific topics, products, or solutions. It involves building consistent brand mentions across authoritative sources that LLMs use as training data.

AI Crawler

AI crawlers are web crawlers operated by AI companies to collect and index web content for use in AI search results and model training. Major AI crawlers include GPTBot and OAI-SearchBot (OpenAI/ChatGPT), ClaudeBot and Claude-SearchBot (Anthropic/Claude), PerplexityBot (Perplexity), and Google-Extended (Gemini).

AI Citation

An AI citation occurs when an AI search engine (ChatGPT, Claude, Perplexity, Google AI Overviews) references your content as a source in its generated response, typically with a link back to your page. Citations are distinct from mentions (brand named without a link) and recommendations (AI actively recommends your product).

AI Overview (Google)

AI Overviews (formerly Search Generative Experience / SGE) are AI-generated answer summaries that appear at the top of Google search results for qualifying queries. They synthesize information from multiple sources and display expandable citation cards linking to the referenced pages.

llms.txt

llms.txt is a proposed web standard (similar to robots.txt) that provides AI crawlers with a curated shortlist of a site's most important pages and their descriptions. It gives LLMs explicit guidance on which content to prioritize when learning about a website.

Core Web Vitals

Core Web Vitals are a set of specific page experience metrics that Google uses as ranking signals: LCP (Largest Contentful Paint) measuring loading speed, INP (Interaction to Next Paint) measuring interactivity, and CLS (Cumulative Layout Shift) measuring visual stability.

LCP (Largest Contentful Paint)

Largest Contentful Paint (LCP) measures how long it takes for the largest visible content element (usually a hero image, video, or large text block) to render on screen. Google's threshold is under 2.0 seconds for a 'good' score (lowered from 2.5s after the March 2026 update).

FCP (First Contentful Paint)

First Contentful Paint (FCP) measures the time from when the page starts loading to when any content (text, image, SVG) is first rendered on screen. Target is under 0.4 seconds for AI search optimization, under 1.8 seconds for a 'good' Google score.

INP (Interaction to Next Paint)

Interaction to Next Paint (INP) measures the responsiveness of a page to user interactions (clicks, taps, key presses) by tracking the time from the interaction to the next visual update. It replaced FID (First Input Delay) as a Core Web Vital in March 2024. Target: under 200ms.

CLS (Cumulative Layout Shift)

Cumulative Layout Shift (CLS) measures the visual stability of a page by quantifying how much the visible content shifts during loading. It scores unexpected layout shifts caused by images without dimensions, dynamically injected content, web fonts, and ads. Target: under 0.1.

Page Speed

Page speed refers to how quickly a web page loads and becomes interactive, encompassing metrics like TTFB (Time to First Byte), FCP, LCP, and total load time. Google uses page speed as a ranking signal via Core Web Vitals, and it directly affects both user experience and AI search citations.

Organic Traffic

Organic traffic is the volume of visitors who arrive at your website through unpaid search engine results. In Google Analytics 4 (GA4), it's tracked as sessions where the source/medium is google/organic, bing/organic, or other search engines. It excludes paid ads, direct visits, referral traffic, and social traffic.

CTR (Click-Through Rate)

Click-Through Rate (CTR) is the percentage of people who click on your search result after seeing it. It's calculated as clicks divided by impressions. In Google Search Console, CTR is reported per query and per page.

Keyword Rankings

Keyword rankings refer to the position at which your website appears in search engine results pages (SERPs) for specific search queries. Rankings are tracked by position (1-100+), with positions 1-10 being page 1 of Google results.

Rich Results

Rich results (formerly called rich snippets) are enhanced search result formats that display additional visual information beyond the standard title, URL, and description. Examples include star ratings, FAQ dropdowns, recipe cards, product prices, event dates, and how-to steps.

Search Visibility (Share of Voice)

Search visibility (also called share of voice or SOV) measures the percentage of total available search impressions your website captures across a defined keyword set compared to competitors. It's a more comprehensive metric than individual keyword rankings because it accounts for search volume and SERP features.

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SEO Glossary

Technical SEO

Crawl Budget

Canonical Tag

Robots.txt

Redirect Chain

301 Redirect

XML Sitemap

Noindex

Indexation

Hreflang

Orphan Page

Structured Data

Schema Markup

HTTPS

Duplicate Content

Internal Linking

On-Page SEO

Title Tag

Meta Description

H1 Tag

Alt Text (Alternative Text)

E-E-A-T

Keyword Cannibalization

Content Structure

Image Optimization

Off-Page SEO

Backlink

Domain Authority

Link Equity

Referring Domain

Anchor Text

AI & GEO

GEO (Generative Engine Optimization)

AEO (Answer Engine Optimization)

LLM Seeding

AI Crawler

AI Citation

AI Overview (Google)

llms.txt

Core Web Vitals

Core Web Vitals

LCP (Largest Contentful Paint)

FCP (First Contentful Paint)

INP (Interaction to Next Paint)

CLS (Cumulative Layout Shift)

Page Speed

Analytics & Metrics

Organic Traffic

CTR (Click-Through Rate)

Keyword Rankings

Rich Results

Search Visibility (Share of Voice)

A-Z Index

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Know the terms. Now fix the issues.