Core Concepts
Before getting into tactics, it helps to understand how search engines work at a basic level. These foundational terms explain how search engines discover, store, and rank content, and how people interact with the results they see. Nearly every other term in this glossary builds on these ideas.
SEO (Search Engine Optimization): The practice of improving a website so it ranks higher and gets more organic traffic from search engines.
SERP (Search Engine Results Page): The page a search engine shows after someone types a query.
Organic Traffic: Unpaid visitors who land on a site from search engine results.
Crawling:
The process where search engine bots read a website's code and content to discover pages.
Indexing: Storing and organizing the pages found during crawling so they can show up in search results.
Search Engine: A program that discovers, indexes, and ranks web pages to answer user queries.
Algorithm: The set of rules and calculations a search engine uses to decide which pages to rank and in what order.
Query: The word or phrase a person types or speaks into a search engine.
Search Intent: What a user actually wants or hopes to find when they type a query — informational, navigational, transactional, or commercial.
Organic Search Results: Unpaid listings that appear because a search engine considers them relevant to the query.
SERP Features: Any non-standard result on a search page, like featured snippets, local packs, or AI Overviews.
Zero-Click Search: A search where the user gets their answer directly on the results page and never clicks through to a website.
On-Page SEO (Content and Code)
On-page SEO covers everything you control directly on your own website, from the words on the page to the HTML behind it. These terms describe how content and code work together to show search engines what a page is about and whether it deserves to rank. Getting these elements right is often the fastest way to improve a page’s visibility.
Title Tag: The main HTML title of a webpage that shows up on search results.
Meta Description: A short text summary in the HTML code that describes what a page is about, often shown under the title in search results.
H1 Tag: The main visible heading on a specific webpage.
Header Tags (H2–H6): Subheadings that organize a page's content and help both readers and search engines understand its structure.
Search Intent: See Core Concepts.
Keywords: Words and phrases that people type into search engines.
E-E-A-T: Stands for Experience, Expertise, Authoritativeness, and Trustworthiness; guidelines Google uses to measure content quality.
Alt Text: A short description added to an image's HTML so search engines and screen readers can understand what it shows.
Internal Linking: Links between pages on the same website that help both users and search engines navigate and understand site structure.
URL Slug: The specific, readable part of a web address that identifies a page.
Keyword Density: The percentage of a page's text made up of a target keyword; largely obsolete as a ranking tactic today.
Keyword Stuffing: Overusing a keyword unnaturally in an attempt to manipulate rankings; considered a spam signal.
Topical Authority: A site's demonstrated depth of expertise on a subject, built through comprehensive, interconnected content.
Featured Snippet: A highlighted answer box that can appear above standard search results, often pulled from a well-structured page.
Content Freshness: How recently a page has been updated with accurate, relevant information.
Off-Page SEO and Links
Off-page SEO focuses on signals that come from outside your website, with backlinks being the most influential. Search engines treat links from other sites as votes of confidence, so the quality and relevance of those links matter a great deal. These terms cover how links pass authority and how sites earn them.
Backlinks: Links from other websites that point to your site.
Anchor Text: The clickable, visible text in a hyperlink.
Domain Authority (DA): A third-party score that predicts how well a website will rank on search engines.
Link Building: The practice of earning backlinks to a website to improve its authority and rankings.
White Hat Link Building: Earning backlinks through ethical, search-engine-compliant methods that focus on relevance and value.
Digital PR: A link building discipline that combines outreach, data studies, and media pitching to earn editorial backlinks.
Guest Posting: Contributing content to another website, often in exchange for a backlink.
Nofollow Link: A link attribute that tells search engines not to pass ranking value through that link.
Link Equity (Link Juice): The authority or trust value passed from one page to another through a link.
Referring Domain: A unique website that links to your site, regardless of how many individual links it contains.
Unlinked Mention: A reference to a brand or business online that doesn't include a hyperlink back to the site.
Disavow: A tool that tells Google to ignore specific backlinks, typically used to address spammy or low-quality links.
Technical SEO
Technical SEO makes sure search engines can crawl, understand, and index a website without running into problems. Even strong content can struggle to rank if technical issues get in the way. These terms cover the behind-the-scenes setup that keeps a site fast, accessible, and easy for search engines to process.
Canonical URL: A tag that tells search engines which version of a webpage is the main or preferred one when duplicate content exists.
Core Web Vitals: Metrics that measure how fast a page loads, how fast it responds to users, and how stable it looks while loading.
Robots.txt: A file that tells search engine crawlers which pages or sections of a site they can and can't access.
Sitemap: A file listing a website's important URLs, submitted to help search engines discover and understand a site's structure.
Noindex: A directive that tells search engines not to include a specific page in search results.
Mobile-First Indexing: Google's practice of using the mobile version of a page as the primary version for indexing and ranking.
HTTPS:
A secure version of a website's connection protocol; a confirmed, though lightweight, ranking signal.
301 Redirect: A permanent redirect from one URL to another that passes along most of the original page's ranking value.
Structured Data (Schema Markup): Code added to a page that helps search engines understand its content and can enable rich results.
JavaScript SEO: The practice of ensuring content built with JavaScript can still be crawled and indexed properly by search engines.
Crawl Budget: The number of pages a search engine is willing to crawl on a given site within a certain timeframe.
Duplicate Content: Identical or very similar content that appears on more than one URL, which can dilute ranking signals.
Page Speed: How quickly a webpage loads; a factor in both user experience and Core Web Vitals.
Local SEO
For businesses that serve customers in a specific area, local SEO determines whether they show up when nearby searchers are looking for them. Google uses a distinct set of signals to rank local results, especially in Maps and the local pack. These terms explain how businesses build and maintain visibility in their communities.
Google Business Profile (GBP): The free business listing that controls how a business appears in Google Maps and local search results.
Local Pack (Map Pack): The map and set of local business listings shown for location-based search queries.
NAP (Name, Address, Phone): The core identifying information for a business, which should stay consistent across all online listings.
Local Citation: An online mention of a business's name, address, and phone number, typically on a directory site.
Local SEO: The practice of optimizing a business's online presence to improve visibility in local search and map results.
Proximity: The physical distance between a searcher and a business; one of Google's core local ranking factors.
AI Search
AI is changing how search results are delivered, with tools like AI Overviews and ChatGPT answering questions directly instead of just listing links. That shift has introduced new vocabulary around how content gets cited and surfaced in AI-generated answers. These terms help explain where search is heading and how traditional SEO carries over into AI visibility.
AI Overviews: AI-generated summaries that can appear at the top of Google search results, often citing multiple sources.
AEO (Answer Engine Optimization): Structuring content so it can be easily extracted as a direct answer by voice assistants, featured snippets, or AI summaries.
LLM (Large Language Model): The type of AI model (like ChatGPT or Gemini) that powers many modern AI search and chat tools.
AI Visibility: A measure of how often and how prominently a brand or website is cited across AI-generated answers.
Citation (AI): A linked source credited within an AI-generated answer, similar in concept to a traditional search ranking.
Grounding: The process of anchoring an AI-generated response to real, retrieved web sources rather than relying purely on trained knowledge.
AI Mode: Google's fully AI-powered search experience, designed for more exploratory or multi-step queries.
Zero-Click Search: See Core Concepts; increasingly relevant as AI Overviews answer more queries directly on the results page.
FAQs
What is SEO in simple terms?
SEO is the practice of improving a website so it ranks higher in search results and attracts more visitors without paying for ads.
What's the difference between on-page and off-page SEO?
On-page SEO covers elements you control directly on your website, like title tags and content. Off-page SEO covers external signals, primarily backlinks, that build a site's authority.
What is GEO, and is it different from SEO?
GEO (Generative Engine Optimization) is the practice of optimizing content to be cited by AI tools like AI Overviews and ChatGPT. It builds on core SEO fundamentals rather than replacing them — the same authority and clarity signals that help traditional rankings also improve AI visibility.
Do I need to know all of these terms to do SEO well?
No. Most SEO work centers on a smaller set of core concepts — search intent, keywords, backlinks, and technical health. This glossary is meant as a reference to return to as specific terms come up in reports, audits, or strategy conversations.
Putting These Terms to Work
Understanding SEO vocabulary is useful, but the real value comes from applying it: aligning content with search intent, earning quality backlinks, keeping technical fundamentals healthy, and now, making sure that authority carries over into AI search results too.
If you're managing SEO for clients and want a partner to help execute on these fundamentals at scale, Semify's
White Label SEO and
AIO programs are built to cover both the traditional and AI sides of search visibility.
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