SEO Fundamentals
SEO Glossary: Plain-English Definitions of SEO, AI Search and Technical Terms
The words agencies and tools use, explained in a sentence or two, with a link to the full guide when you need more.
SEO has its own vocabulary, and AI search has added a new layer of acronyms. This glossary covers the terms you’re most likely to meet in reports, proposals and tools.
Definitions follow Google’s own documentation where Google defines the term.
Short answer: This SEO glossary defines common terms in plain English: crawling, indexing and ranking; on-page terms like title links, meta descriptions and canonical tags; technical terms like robots.txt, noindex, sitemaps and Core Web Vitals; local terms like Business Profile and NAP; and AI search terms such as AI Overviews, AEO, GEO and LLM.
Key Takeaways
- Crawling, indexing and serving are Google’s three stages.
- Most technical terms are about access and duplicates.
- AEO, GEO and LLM SEO describe optimizing for AI answers.
- Metrics in tools (DA, keyword difficulty) are third-party estimates.
- Use the linked guides for depth.
How search works
| Term | Meaning |
|---|---|
| Crawling | Automated programs (crawlers) fetch pages they discover, mostly through links (how search works). |
| Indexing | Google analyzes a page and may store it in its index. Not every crawled page is indexed. |
| Ranking / serving | Choosing and ordering results for a query (how Google ranks pages). |
| SERP | Search engine results page: everything shown for a query (SERP features). |
| Search intent | What the searcher wants to do or find (search intent). |
| PageRank | Google’s link analysis system; Google says it’s still one of many signals. |
On-page terms
| Term | Meaning |
|---|---|
| Title link | The clickable headline in results, usually from the title tag (title tags). |
| Meta description | A page summary Google sometimes uses as the snippet (meta descriptions). |
| H1 / headings | Visible headings that structure the page. |
| Alt text | Text describing an image for screen readers and search engines (image SEO). |
| Internal link / anchor text | A link between your own pages and its clickable words (internal linking). |
| E-E-A-T | Experience, expertise, authoritativeness, trust: concepts from Google’s rater guidelines, not a single ranking factor (E-E-A-T). |
| Keyword cannibalization | Several of your pages competing for the same intent (cannibalization). |
Technical terms
| Term | Meaning |
|---|---|
| robots.txt | A file telling crawlers which paths not to crawl; not a way to keep pages out of the index (noindex vs robots.txt). |
| noindex | A robots meta tag or header telling Google not to index a page. |
| Canonical tag | Your preferred URL among duplicates (canonicals). |
| XML sitemap | A file listing URLs you want discovered (sitemaps). |
| 301 / 302 | Permanent and temporary redirects (status codes). |
| Soft 404 | A page that looks like an error but returns 200. |
| Core Web Vitals | Google’s metrics for loading (LCP), responsiveness (INP) and visual stability (CLS) (CWV). |
| Crawl budget | How much Google can and wants to crawl on a site; mostly a large-site concern (crawl budget). |
| Structured data / schema | Code that describes page content in a standard format (structured data). |
| hreflang | Markup linking language or country versions of a page (hreflang). |
| Mobile-first indexing | Google mainly uses the mobile version of content for indexing and ranking. |
Local SEO terms
| Term | Meaning |
|---|---|
| Google Business Profile | Your free business listing on Google Search and Maps (GBP checklist). |
| Map Pack / local pack | The map with business listings shown for local searches (Map Pack). |
| NAP | Name, address, phone: business details that should match everywhere (citations). |
| Citation | A mention of your business details on another site or directory. |
| Service-area business | A business that visits customers rather than serving them at its address (SAB SEO). |
| Relevance, distance, prominence | Google’s three main local ranking factors. |
AI search terms
| Term | Meaning |
|---|---|
| AI Overviews | Google’s AI-generated summaries in Search results (AI search). |
| AI Mode | Google’s conversational AI search experience (AI Mode). |
| LLM | Large language model: the technology behind ChatGPT, Gemini, Claude and others (LLM SEO). |
| AEO | Answer engine optimization: making content easy to use as a direct answer (AEO). |
| GEO | Generative engine optimization: improving visibility in AI-generated answers (GEO). |
| Citation (AI) | A link or source an AI answer credits. |
| Grounding / retrieval | When an AI system fetches current web results to base its answer on. |
| AI crawler | A bot fetching content for AI training or search, such as GPTBot or PerplexityBot (AI crawlers). |
| llms.txt | A proposed file summarizing a site for language models; not a Google standard (llms.txt). |
| Entity | A distinct thing (business, person, product) search systems can recognize (entities). |
Metrics and tool terms
| Term | Meaning |
|---|---|
| Impressions / clicks / CTR / position | Search Console performance metrics (Performance report). |
| Search volume | Estimated monthly searches; tools disagree (volume and difficulty). |
| Keyword difficulty | A tool’s estimate of ranking difficulty, not a Google metric. |
| Domain Authority / Authority Score | Third-party link scores; Google doesn’t use them (DA explained). |
| Key event (GA4) | An action you mark as important, formerly called a conversion (GA4 conversions). |
| Branded vs non-branded | Searches with or without your brand name (branded traffic). |
Frequently asked questions
What’s the difference between SEO, AEO and GEO?
SEO covers search visibility broadly; AEO and GEO focus on direct answers and AI-generated results. See AEO vs SEO.
Is E-E-A-T a ranking factor?
Google says E-E-A-T itself isn’t a specific ranking factor; it describes qualities its systems try to reward.
Are Domain Authority and keyword difficulty Google metrics?
No. They are estimates created by SEO tool companies.
Not sure where your site stands?
Request a free SEO audit. We’ll check indexing, technical health and your key pages, and tell you what to fix first.
Sources
- Google Search Central: SEO Starter Guide
- Google Search Central: In-depth guide to how Google Search works
- Google Search Central: A guide to Google Search ranking systems
- Google Search Central: AI features and your website
- Google Search Central: Creating helpful, reliable, people-first content
Last reviewed October 14, 2026.
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