SEO Glossary
Plain-English definitions of the terms, acronyms, and concepts every SEO professional needs to know.
A
Algorithm Update
A change to Google's search ranking algorithms that can cause significant shifts in search engine results pages (SERPs). Major updates include Panda, Penguin, Hummingbird, and the more recent Helpful Content updates.
Alt Text
Alternative text added to an image's HTML tag that describes the image for screen readers and search engines. Proper alt text improves accessibility and can help images rank in Google Images.
Anchor Text
The clickable text of a hyperlink. Search engines use anchor text as a ranking signal to understand what the linked page is about. Exact-match anchor text can be over-optimized.
B
Backlink
A link from one website to another. Backlinks are one of the most important ranking factors in SEO, serving as a signal of trust and authority. Quality matters more than quantity.
Bounce Rate
The percentage of visitors who leave a website after viewing only one page. A high bounce rate can indicate poor user experience or content that doesn't match search intent.
C
Canonical Tag
An HTML element that tells search engines which version of a page is the preferred or original one when duplicate or similar content exists. Prevents duplicate content issues.
Core Web Vitals
A set of three metrics (LCP, FID/INP, CLS) that measure real-world user experience in terms of loading performance, interactivity, and visual stability. They are confirmed Google ranking factors.
Crawl Budget
The number of pages a search engine bot will crawl on your site within a given time period. Large sites with many pages need to optimize their crawl budget to ensure important pages are discovered.
D
Domain Authority
A search engine ranking score developed by Moz that predicts how likely a website is to rank in search engine result pages. Scores range from 1 to 100, with higher scores corresponding to greater likelihood of ranking.
Duplicate Content
Content that appears on the internet in more than one place. When multiple pages contain substantially identical content, search engines may struggle to determine which version is most relevant to a search query.
E
E-E-A-T
Experience, Expertise, Authoritativeness, and Trustworthiness. A framework Google uses to evaluate content quality, particularly for Your Money Your Life (YMYL) topics. First-hand experience is now explicitly valued alongside traditional expertise signals.
External Link
A hyperlink that points from your website to a different domain. High-quality outbound links to authoritative sources can improve your own site's credibility and user experience.
F
Featured Snippet
A highlighted search result that appears at the top of Google's organic results, designed to answer the user's question directly. Formats include paragraphs, lists, tables, and videos.
Follow vs Nofollow
Rel attributes that tell search engines whether to pass link equity. "Follow" (default) passes authority; "nofollow" tells crawlers not to endorse the linked page. "Sponsored" and "ugc" values provide additional context.
G
Google Business Profile
A free tool that lets businesses manage how they appear on Google Search and Maps. Critical for local SEO, it controls reviews, photos, hours, posts, and Q&A that appear in local pack results.
Google Search Console
A free web service by Google that helps webmasters monitor, maintain, and troubleshoot their site's presence in Google Search results. Provides data on indexing, queries, clicks, and manual actions.
H
Hreflang
An HTML attribute used to specify the language and geographical targeting of a webpage. Essential for multilingual websites to help search engines serve the correct language version to users.
HTTP Status Codes
Three-digit responses from a server indicating the result of a request. 200 means OK, 301 is a permanent redirect, 404 is not found, and 500 indicates a server error. Proper status code management is fundamental to technical SEO.
I
Index Coverage
The set of pages from your site that a search engine has discovered, crawled, and stored in its index. Google Search Console's Index Coverage report shows which pages are indexed and why others are excluded.
Internal Link
A hyperlink from one page on your domain to another page on the same domain. Strategic internal linking distributes PageRank, establishes hierarchy, and helps crawlers discover deep content.
K
Keyword Cannibalization
When multiple pages on the same website target the same keyword, causing them to compete against each other in search results. This dilutes ranking potential and should be resolved through consolidation.
Keyword Difficulty
A metric that estimates how hard it would be to rank on the first page of Google for a specific keyword. It is typically based on the authority of the current top-ranking pages.
L
LCP (Largest Contentful Paint)
A Core Web Vital metric measuring the time it takes for the largest visible content element to render within the viewport. Google considers 2.5 seconds or less to be a good LCP score.
Local Pack
The map and list of three local business results that appears for queries with local intent. Ranking in the local pack requires Google Business Profile optimization, local citations, and review generation.
M
Meta Description
A brief summary of a webpage's content that appears in search engine results below the title tag. While not a direct ranking factor, compelling meta descriptions improve click-through rates.
Mobile-First Indexing
Google's practice of using the mobile version of a webpage for indexing and ranking. Since 2019, Google predominantly crawls and indexes the mobile version of sites rather than the desktop version.
N
Nofollow
A rel attribute value that instructs search engines not to follow a link or pass link equity. Commonly used for user-generated content, sponsored links, and untrusted sources.
O
Organic Traffic
Visitors who arrive at your website through unpaid search engine results. Organic traffic is typically the highest-intent, most sustainable source of website visitors for content-driven businesses.
Orphan Page
A webpage that has no internal links pointing to it from other pages on the same site. Without links, crawlers cannot discover orphan pages unless they are submitted in a sitemap or linked externally.
P
PageRank
Google's original algorithm for measuring the importance of web pages based on the quantity and quality of links pointing to them. While no longer the sole ranking factor, link-based authority remains fundamental to SEO.
Pillar Page
A comprehensive, long-form piece of content that broadly covers a core topic and links to related cluster content. Pillar pages typically target broad, high-volume keywords and serve as the hub of a content cluster.
R
Robots.txt
A text file at the root of a website that instructs search engine crawlers which pages or files they can or cannot request. It is a guideline, not a security mechanism, and should be paired with noindex tags for sensitive content.
Rich Snippet
An enhanced search result that displays additional visual or informational elements beyond the standard title, URL, and description. Enabled by structured data markup, rich snippets can include ratings, prices, event dates, and more.
S
Schema Markup
Structured data code added to web pages to help search engines understand the content better. It can enable rich snippets in search results, such as star ratings, recipe details, and event information.
Search Intent
The underlying goal a user has when typing a query into a search engine. The four main types are informational, navigational, transactional, and commercial investigation.
SERP
Search Engine Results Page. The page displayed by a search engine in response to a query. Modern SERPs include organic results, paid ads, featured snippets, knowledge panels, and other rich features.
T
Title Tag
The HTML element that specifies the title of a web page, displayed on search engine results pages as the clickable headline. Title tags are a confirmed ranking factor and should be unique, descriptive, and under 60 characters.
Technical SEO
The practice of optimizing a website's infrastructure so search engines can crawl, index, and render it effectively. Includes site speed, mobile usability, crawlability, security, and structured data.
U
User Experience (UX)
The overall experience a visitor has when interacting with a website. Google's ranking systems increasingly prioritize pages that offer fast load times, intuitive navigation, and satisfying content that matches search intent.
V
Voice Search
Search queries spoken aloud to digital assistants like Siri, Google Assistant, or Alexa. Voice searches tend to be longer, more conversational, and question-based than typed queries, requiring different content optimization strategies.
W
White Hat SEO
Ethical SEO practices that follow search engine guidelines and focus on human audiences. White hat techniques include quality content creation, legitimate link building, and technical optimization. The opposite of black hat SEO.