A
Algorithm
The set of rules and calculations a search engine uses to decide which pages to return for a query and in what order. Modern search algorithms combine hundreds of signals — relevance, authority, page experience, and increasingly machine-learned relevance models.
AI Overviews
Google's AI-generated summary that appears above traditional organic results for many queries, synthesizing information from multiple sources into a single answer. Formerly known as the Search Generative Experience (SGE) during testing.
Why it matters: AI Overviews can reduce click-through to source websites even when those sites are cited, making visibility inside the summary itself a growing SEO concern.
Anchor Text
The clickable, visible text of a hyperlink. Search engines use anchor text as a relevance signal for the page being linked to, which is why manipulated or over-optimized anchor text was a key target of the Penguin update.
B
Backlink
An inbound link from one website to another. Backlinks remain one of the core signals behind PageRank-style ranking, functioning as a vote of confidence from the linking site.
BERT
Bidirectional Encoder Representations from Transformers — a Google language model deployed in 2019 to better understand the context and nuance of search queries, particularly natural-language and conversational phrasing.
Bounce Rate
The percentage of visitors who leave a site after viewing only one page. Often cited in SEO discussions, though search engines have downplayed its direct use as a ranking signal in favor of more granular engagement metrics.
C
Canonical Tag
An HTML tag (rel="canonical") that tells search engines which version of a duplicate or near-duplicate page should be treated as the authoritative one for indexing and ranking purposes.
Why it matters: Incorrect or missing canonicalization is one of the most common technical SEO issues found in enterprise-scale website audits, often splitting ranking signals across duplicate URLs.
Crawl Budget
The number of pages a search engine's crawler will fetch from a site within a given time frame. Large or technically inefficient sites can exhaust crawl budget before important pages are reached, delaying indexing.
Crawling
The process by which a search engine's automated bots (crawlers or spiders) discover pages by following links, before those pages can be indexed and ranked.
CTR (Click-Through Rate)
The percentage of people who click a result after seeing it in the search results. Title tags and meta descriptions are commonly optimized to improve CTR, independent of ranking position.
D
Deindexing
The removal of a page or entire site from a search engine's index, either voluntarily (via a noindex tag) or as a manual or algorithmic penalty for violating search engine guidelines.
Directory (Web Directory)
A human-curated list of websites organized into categories, the dominant search model of the mid-1990s (Yahoo! Directory being the best-known example) before algorithmic, crawler-based ranking took over.
Duplicate Content
Substantially identical content appearing at more than one URL, whether on the same site or across different domains, which can dilute ranking signals and cause search engines to choose which version to show.
E
E-E-A-T
Experience, Expertise, Authoritativeness, and Trustworthiness — the framework Google's Search Quality Rater Guidelines use to describe the qualities of content and sites that deserve to rank well, particularly for topics affecting health, finances, or safety.
Entity
A distinct, identifiable thing — a person, place, organization, or concept — that a search engine can recognize and connect to related facts, typically via a knowledge graph, independent of the specific words used to describe it.
Exact-Match Domain (EMD)
A domain name that matches a target keyword phrase exactly (for example, searchengines.net for content about search engines). EMDs lost much of their automatic ranking advantage after Google's 2012 EMD update, though they retain value for branding, direct type-in traffic, and topical clarity.
F
Featured Snippet
A highlighted answer box shown above standard organic results, pulled directly from a ranking page's content and typically formatted as a paragraph, list, or table.
Fetch and Render
The process by which a search engine retrieves a page's raw code and then executes its JavaScript to see the page as a browser would — a critical concept in JavaScript SEO, since content that never renders can go unindexed.
G
GEO (Generative Engine Optimization)
The emerging practice of optimizing content to be accurately cited, summarized, or surfaced by generative AI systems such as AI Overviews, Perplexity, and ChatGPT — a discipline running parallel to, and increasingly overlapping with, traditional SEO.
Google Search Console
Google's free platform for site owners to monitor indexing status, search performance, crawl errors, and manual actions — the primary diagnostic tool for technical SEO work involving Google.
H
Hreflang
An HTML attribute that tells search engines which language and regional version of a page to serve to users, central to international SEO for sites operating across multiple countries or languages.
Hummingbird
A 2013 Google algorithm update that shifted ranking toward understanding the intent and meaning behind a full query rather than matching individual keywords, an early step toward natural-language search.
I
Index / Indexing
The process of storing and organizing crawled pages so they can be retrieved and ranked in response to a search query. A page can be crawled without being indexed if it is deemed low-value, duplicate, or blocked.
Internal Linking
Hyperlinks connecting pages within the same site, used to distribute authority, establish site architecture, and help search engines understand the relative importance and topical relationship of pages.
Intent (Search Intent)
The underlying goal behind a search query — commonly categorized as informational, navigational, transactional, or commercial investigation — which search engines attempt to infer and match with the most appropriate result format.
J
JSON-LD
The recommended format for implementing structured data (schema markup) on a webpage, written as a self-contained script block rather than embedded inline in HTML tags, which search engines parse to understand page content more precisely.
L
Link Farm
A network of websites created solely to link to one another (or to a target site) in order to manipulate PageRank and search rankings — a practice directly targeted by Google's Penguin update.
Local Pack
The map-based set of local business results (typically three listings) shown for location-relevant queries, drawing primarily from Google Business Profile data rather than standard web ranking signals.
Long-Tail Keyword
A longer, more specific search phrase that typically has lower search volume but higher conversion intent than a short, broad "head" keyword.
M
Meta Description
An HTML tag providing a short summary of a page's content. It is not a direct ranking factor, but a well-written meta description influences click-through rate from the results page.
Mobile-First Indexing
Google's practice, fully rolled out by 2019, of using the mobile version of a site's content as the primary basis for indexing and ranking, reflecting the shift of most search traffic to mobile devices.
N
Natural Language Processing (NLP)
The branch of machine learning concerned with understanding and generating human language, underlying technologies from Hummingbird and BERT through today's large language model-powered AI search.
Noindex Tag
A meta tag or HTTP header instructing search engines not to include a specific page in their index, commonly used for thin, duplicate, or low-value pages that should remain accessible to users but not appear in search results.
O
Off-Page SEO
Ranking factors that occur outside a website itself, primarily backlinks, brand mentions, and other external signals of authority and trust.
Organic Search Results
Unpaid search listings ranked according to relevance and authority, as distinct from paid search ads, shopping listings, or AI-generated overviews.
P
PageRank
The link-analysis algorithm developed by Larry Page and Sergey Brin, published in 1998, that scores a page's importance based on the quantity and quality of links pointing to it. PageRank was the foundational innovation behind Google's early dominance in search.
Panda
A 2011 Google algorithm update targeting thin, low-quality, and duplicate content, particularly content farms publishing high volumes of low-value pages.
Penguin
A 2012 Google algorithm update targeting manipulative link-building practices, including paid links, link farms, and over-optimized anchor text.
Q
Query
The word or phrase a user types or speaks into a search engine, distinct from the broader "keyword" a website may target, since a single keyword can be expressed through many different query phrasings.
R
RankBrain
A machine-learning system introduced by Google in 2015 to help interpret ambiguous or previously unseen search queries, one of the first major uses of machine learning directly within Google's core ranking algorithm.
Redirect (301/302)
An HTTP status code instructing browsers and search engines to send traffic from one URL to another. A 301 signals a permanent move and passes the vast majority of ranking signals to the new URL; a 302 signals a temporary move and is not intended to pass ranking signals long-term. Using the wrong redirect type is among the most common and costly mistakes in website and domain migrations.
Robots.txt
A text file at a site's root directory that instructs search engine crawlers which sections of a site they may or may not crawl. It controls crawling, not indexing — a blocked page can still be indexed if enough external links point to it.
S
Schema Markup
Structured data, typically written in JSON-LD, that labels page content in a standardized vocabulary (schema.org) so search engines can understand it more precisely and potentially display it as a rich result.
SERP (Search Engine Results Page)
The full page of results returned for a query, now typically composed of paid ads, organic listings, AI Overviews, featured snippets, local packs, and other specialized result types rather than a simple list of ten blue links.
Sitemap (XML Sitemap)
A file listing a site's important URLs, submitted to search engines to aid discovery and crawling, particularly useful for large sites or pages with few internal links pointing to them.
T
Technical SEO
The discipline of ensuring a website can be properly crawled, indexed, and ranked — covering site architecture, crawl optimization, canonicalization, structured data, Core Web Vitals, and JavaScript rendering, among other factors.
Title Tag
The HTML element defining a page's title, displayed as the clickable headline in most search results and browser tabs, and one of the most influential on-page relevance signals.
Topical Authority
The degree to which a search engine views a site as a comprehensive, trustworthy source on a given subject, typically built through depth and breadth of coverage on a topic rather than any single page.
U
UDRP (Uniform Domain-Name Dispute-Resolution Policy)
ICANN's policy for resolving disputes over domain names registered in bad faith or in violation of trademark rights, adjudicated by approved dispute-resolution providers rather than the courts in most cases.
URL Structure
The organization and format of a site's web addresses, which affects crawl efficiency, user understanding, and the clarity of a site's information hierarchy to both users and search engines.
V
Voice Search
Search queries spoken aloud to a device or assistant (Siri, Alexa, Google Assistant), which tend to be longer and more conversational than typed queries and favor concise, direct-answer content.
W
WHOIS
The public lookup protocol for domain registration records, historically used to identify a domain's registrant, though privacy services and GDPR-driven redaction have significantly limited the ownership detail publicly visible today.
White Hat SEO
SEO practices that comply with search engine guidelines and focus on genuine value to users, as distinct from "black hat" tactics designed to manipulate rankings in ways that violate those guidelines.
X
XML Sitemap
See Sitemap. A machine-readable file format (as opposed to an HTML sitemap intended for human visitors) listing URLs for search engine consumption.
Z
Zero-Click Search
A search query that is fully answered on the results page itself — via a featured snippet, knowledge panel, or AI Overview — without the user clicking through to any website. The rising share of zero-click searches is a central concern in the AI search era.