SEO Tool
Glossary
SEO glossary
47 SEO terms explained in plain English, with links to the guide or tool that goes deeper.
A
- AI Overview
- An AI-generated summary Google shows above the organic results for some searches, with links to the sources it used. Being cited in one can bring clicks even when you do not rank first. Track AI Overview citations →
- AI visibility
- How often AI assistants such as ChatGPT, Gemini, Claude and Perplexity mention or cite a brand when answering relevant questions. Also called generative engine optimisation (GEO) or answer engine optimisation (AEO). Guide to AI search visibility →
- Alt text
- A short text description of an image in the HTML alt attribute. It helps screen-reader users and tells search engines what the image shows.
- Anchor text
- The visible, clickable words of a link. Descriptive anchor text helps search engines understand the page being linked to.
- Authority Score
- Our 0–100 measure of a domain’s or page’s backlink strength: DataForSEO’s rank divided by ten. It is not the same as Ahrefs Domain Rating or Semrush Authority Score. How it is calculated →
B
- Backlink
- A link from another website to yours. Links from relevant, trusted sites are one of the strongest signals search engines use to rank pages. Backlink checker →
- Backlink gap
- Domains that link to one or more of your competitors but not to you. Also called link intersect. One of the best sources of link-building prospects. Backlink gap guide →
- Broken backlink
- A link from another site that points to a page on your site that no longer exists. Redirecting the dead URL recovers the value of the link.
C
- Canonical tag
- A rel="canonical" link in a page’s head that tells search engines which URL is the preferred version when several URLs show the same or very similar content.
- Click-through rate (CTR)
- The percentage of people who see a result and click it. In search it falls sharply with position: the first result gets far more clicks than the fifth. Our CTR curve →
- Content gap
- Keywords that one or more competitors rank for and you do not. A quick way to find topics your site is missing. Competitor analysis →
- Core Web Vitals
- Google’s three page-experience metrics: Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability).
- Crawl budget
- How many pages a search engine is willing and able to crawl on your site in a given time. It matters mostly for large sites, where wasted crawling on duplicates or redirects can delay important pages.
- Crawler
- A program that visits web pages by following links, also called a bot or spider. Search engines use crawlers to discover pages; SEO tools use them to audit sites.
D
- Domain Rating (DR)
- Ahrefs’ 0–100 measure of a domain’s backlink strength. Other tools have similar but different metrics, so values cannot be compared across tools. Why scores differ between tools →
F
- Featured snippet
- A highlighted answer shown at the top of some Google results, taken from one of the ranking pages, with a link to it.
G
- Google Business Profile
- The free listing that controls how a business appears in Google Maps and the local pack: name, address, hours, photos, posts and reviews. Local SEO tools →
H
- Health score
- A 0–100 summary of a site’s technical health from a site audit, used to track progress from crawl to crawl. Website audit →
- hreflang
- An attribute that tells search engines which language and country each version of a page is for, so the right version appears in each market.
I
- Indexing
- Adding a page to a search engine’s database so it can appear in results. A page can be crawled but not indexed, for example if it has a noindex tag or is judged a duplicate.
- IndexNow
- A protocol that lets a site notify participating search engines (such as Bing) immediately when pages are added, changed or deleted.
- Internal link
- A link from one page on your site to another. Internal links help search engines discover pages and understand which ones you consider most important.
K
- Keyword cannibalization
- When two or more of your pages compete for the same search query and hold each other back. Usually fixed by merging pages or making their intent clearly different. How to fix it →
- Keyword clustering
- Grouping keywords that one page can rank for, ideally by comparing which pages search engines rank for each keyword. Keyword clustering guide →
- Keyword difficulty (KD)
- A 0–100 estimate of how hard it is to reach the first page for a keyword, based mainly on the backlink strength of the pages already ranking. Keyword difficulty explained →
L
- Local grid
- A map of rank checks for one keyword from a grid of points around a location, showing how map rankings change across a service area. Rank tracker →
- Local pack
- The block of map results (usually three businesses) that Google shows for searches with local intent. Local SEO checklist →
- Log file analysis
- Reading your web server’s access logs to see exactly which pages search engine and AI bots request, how often, and which errors they meet.
M
- Meta description
- A short summary of a page in its HTML head. Search engines often show it under the title in results, so it influences clicks even though it is not a ranking factor.
N
- NAP
- A business’s Name, Address and Phone number. Consistent NAP across directories and maps helps local rankings.
- Nofollow
- A rel="nofollow" attribute on a link that asks search engines not to pass ranking credit through it. rel="ugc" and rel="sponsored" are related values for user-generated and paid links.
- Noindex
- A robots meta tag or HTTP header that tells search engines not to include a page in their index.
O
- Organic traffic
- Visits that come from unpaid search results, as opposed to ads, social media, email or direct visits.
P
- People Also Ask
- A Google results feature listing related questions that expand to show short answers from ranking pages.
R
- Redirect chain
- A series of redirects (A to B to C) before reaching the final page. Chains slow crawling and users, and should be replaced with a single redirect.
- Referring domain
- A unique website that links to yours. Ten links from one site count as one referring domain; it is usually a better measure of link popularity than total backlinks.
- robots.txt
- A text file at the root of a site that tells crawlers which paths they may or may not crawl. It controls crawling, not indexing.
S
- Search intent
- What the searcher is trying to do: learn something (informational), compare options (commercial), buy (transactional) or reach a specific site (navigational).
- Search visibility
- The share of available clicks a site earns for a set of tracked keywords, from 0% to 100%, based on search volume and the expected CTR of each position. How visibility is calculated →
- Search volume
- The average number of searches a keyword gets each month in a given market, usually over the last 12 months. Where volume comes from →
- SERP
- Search engine results page: everything a search engine shows for a query, including organic results, ads and SERP features.
- SERP features
- Anything on a results page that is not a standard blue link: featured snippets, AI Overviews, local packs, People Also Ask, images, videos and more.
- Structured data
- Code (usually JSON-LD using schema.org vocabulary) that describes a page’s content to search engines, making it eligible for rich results.
T
- Title tag
- The HTML title of a page. It usually becomes the clickable headline in search results and is one of the most important on-page signals.
U
- Unlinked mention
- A web page that mentions your brand without linking to your site. Because the author already knows you, asking for a link is easy outreach. Brand monitoring →
X
- XML sitemap
- A file listing the URLs you want search engines to crawl and index, often with the date each was last changed.
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