SEO terminology becomes much easier once the terms are separated by job. Some describe how Google finds and processes a page, others describe what appears in search results, and others belong to analytics or third-party SEO tools. Mixing those categories is where beginner reports often become confusing.
Use this glossary as a reference rather than a course. Start with the quick table, then jump to the fuller explanation when a term needs context. If the whole subject is new, the SEO basics guide explains how these pieces fit together.
The SEO Terms Worth Learning First
| Term | Plain-English meaning | Why it matters |
|---|---|---|
| SEO | Improving a site so search engines can understand important pages and users can find useful answers through unpaid search results. | The umbrella discipline. |
| Search query | The words a person actually enters or speaks into a search engine. | Shows the user’s language and immediate task. |
| Keyword | A query or topic an SEO team chooses to research, map or monitor. | Useful for planning, but not identical to the user’s actual query. |
| Search intent | What the searcher is trying to learn, find, compare or do. | Helps determine the right page type and answer. |
| SERP | Search engine results page. | Shows the competing results and search features for a query. |
| Crawling | A search engine fetching a URL and its resources. | A page cannot be processed properly if important content cannot be accessed. |
| Indexing | A search engine analysing content and potentially storing it in its index. | Crawled does not automatically mean indexed. |
| Ranking | The ordering of eligible results for a particular search. | A ranking problem is different from an indexing problem. |
| Canonical URL | The representative URL selected among duplicate or very similar versions. | Helps consolidate duplicate URL signals. |
| 301 redirect | A permanent redirect from one URL to another. | Used when a page has genuinely moved or been replaced. |
| 404 | An HTTP response indicating that the requested resource was not found. | Useful for genuinely removed URLs, but a problem when important links break. |
| Robots.txt | A file that controls crawler access to URL paths. | Controls crawling, not reliable removal from search results. |
| XML sitemap | A file listing URLs you want search engines to know about. | Supports discovery, especially on larger or changing sites. |
| Title tag | The page’s HTML <title> element. | Helps describe the page and can influence the title shown in search. |
| Meta description | A page-level description that Google may use for a search snippet. | Useful for describing the page, but Google can generate another snippet. |
| Alt text | Text in an image’s alt attribute. | Primarily supports accessibility and can also provide image context. |
| Internal link | A link from one page on a site to another page on the same site. | Supports navigation, discovery and page relationships. |
| Backlink | A link to your site from another website. | Can provide referral traffic and external recognition. |
| Core Web Vitals | LCP, INP and CLS, metrics for loading, responsiveness and visual stability. | Useful for measuring important parts of real user experience. |
| CTR | Clicks divided by impressions. | Shows how often a viewed search result receives a click under the reporting system used. |
A glossary should make distinctions clearer, not merely collect acronyms. The next section covers the pairs that are most often mixed together.
SEO Terms People Often Confuse
Crawling, Indexing and Ranking
Google describes Search as three broad stages: crawling, indexing and serving search results. Crawling is the fetching stage. Indexing is where Google analyses content and may store information in its index. Serving is where Google returns results for a query; ranking is the ordering of eligible results within that process. Google also makes clear that following its technical requirements does not guarantee that a page will be crawled, indexed or served. Google’s guide to how Search works explains the stages in detail.
For diagnosis, check the earliest stage that may be failing. Rewriting an article will not repair a blocked URL, and an indexed page with weak query matching is not an indexing problem. The crawling and indexing guide goes deeper into that workflow.
Search Query, Keyword and Search Intent
Search query is the user’s actual wording. Keyword is the term or topic an SEO team chooses to research, organise or track. Search intent is the task behind the query. One keyword can represent several intents, so keyword volume alone does not tell you which page to create.
For example, ‘cake’ could lead to a recipe, a local bakery page or storage advice. The wording is related, but the useful page is not the same.
301 Redirect, 404 and Canonical URL
These solve different URL problems. A 301 redirect sends users and crawlers permanently to another URL. A 404 is appropriate when a resource no longer exists and has no useful replacement. A canonical is used when duplicate or very similar URLs remain accessible but one version should be treated as representative.
Do not use a canonical tag as a substitute for a redirect when a URL has genuinely moved. Likewise, redirecting every deleted page to the homepage creates a poor match between the old request and the new destination.
Title Tag, Title Link and Meta Description
The title tag is the HTML <title> element. The title link is the clickable title Google actually shows in a result. They can differ because Google may use several sources to generate title links. A meta description is separate again: Google may use it for the descriptive snippet, but snippets are primarily generated from page content and can vary by query. Google’s title link guidance and snippet guidance explain these distinctions.
Robots.txt and Noindex
Robots.txt manages crawler access. Noindex tells a compliant search engine not to index a page, but the crawler normally needs to access the page to see that instruction. Google explicitly warns that robots.txt is not a mechanism for keeping a web page out of Search. Google’s robots.txt documentation is the safer reference before changing crawl rules.
Technical SEO Terms
Technical SEO covers the systems that affect discovery, crawling, rendering, indexing, canonicalisation and delivery. For a fuller operational explanation, see what technical SEO is.
Robots.txt
A robots.txt file sits at the root of a host and gives crawler-specific access rules. It is commonly used to reduce crawling of unimportant or repetitive URL areas, and it can also declare sitemap locations. It should not be used to protect private information.
XML Sitemap
An XML sitemap lists URLs that a site wants search engines to know about. Google describes sitemaps as a discovery aid, not an indexing guarantee. For most editorial sitemaps, include the canonical URLs that are intended for indexing and keep the file aligned with real site changes. Google’s sitemap documentation covers supported formats and use cases.
Canonical Tag
A canonical tag, written as rel="canonical", is one way to signal the representative URL for duplicate or very similar pages. Google treats canonicalisation as a signal-selection process, so the tag should agree with other signals such as internal links, redirects and sitemap URLs where practical.
A canonical is not an instruction to hide a page. If a URL should not be indexed at all, use an appropriate indexing control instead. Google’s canonicalisation guidance explains the available methods.
Structured Data and Schema Markup
Structured data is machine-readable markup that describes entities or page content using a supported vocabulary such as Schema.org. In Google Search, valid structured data can make a page eligible for certain search features when the specific feature is supported. It does not guarantee a rich result or a ranking improvement, and the markup must match visible page content. Google’s introduction to structured data explains the current requirements.
Core Web Vitals
Core Web Vitals are Google’s current metrics for key aspects of real-world page experience: Largest Contentful Paint (LCP) for loading, Interaction to Next Paint (INP) for responsiveness and Cumulative Layout Shift (CLS) for visual stability. Google’s current ‘good’ targets are LCP within 2.5 seconds, INP below 200 milliseconds and CLS below 0.1. These metrics should be read as performance diagnostics, not as a complete measure of page quality. Google’s Core Web Vitals documentation provides the current definitions.
Mobile-First Indexing
Mobile-first indexing means Google uses the mobile version of a site’s content, crawled with its smartphone agent, for indexing and ranking. The practical requirement is content and metadata parity: important text, structured data, headings, images and crawl controls should not disappear simply because the screen is smaller. Google’s mobile-first indexing guidance sets out the current requirements.
On-Page and Content SEO Terms
Title Tag
The title tag describes a page in the HTML <title> element. A useful title is descriptive, concise and specific to the page. It should not become a list of repeated keyword variations. Google may use the title element as one source when generating a title link.
Meta Description
A meta description is a page-level summary stored in a <meta name="description"> element. Google may use it to create a search snippet when it is more useful than text taken from the page, but it can generate a different snippet for a particular query. Write it as an accurate page summary rather than treating it as guaranteed display copy.
Alt Text
Alt text is the text value in an image’s alt attribute. Its first job is accessibility: it should communicate the information or function that would otherwise be lost for someone who cannot see the image. Search engines can also use alt text as image context. Decorative images can use an empty alt="" when appropriate.
For the publishing decisions behind image descriptions, decorative images and performance, see MOCOBIN’s image SEO and alt text guide.
Internal Link
An internal link points from one URL on a site to another URL on the same site. Internal links help users move through related information and help crawlers discover pages and understand relationships. Anchor text should describe the destination naturally rather than repeat an exact keyword mechanically.
Heading Tags
Heading tags such as H1, H2 and H3 create a hierarchy for the visible page. They are most useful when they make the document easier to scan and understand. Treat them as structure, not as places that need a keyword at every level.
Keyword Stuffing
Keyword stuffing is the unnatural repetition of words or phrases in copy, links, metadata or other fields in an attempt to influence search visibility. Google lists keyword stuffing in its spam policies. Natural language does not require a fixed keyword density, and repetition that makes a page harder to read is not useful optimisation. Google’s spam policies provide the current examples.
Duplicate Content
Duplicate content describes identical or substantially similar content available at more than one URL. Duplication is not automatically a penalty, but it can create unnecessary crawling, canonicalisation and maintenance problems. The correct response depends on why the duplicate URLs exist: redirect, canonicalise, noindex, consolidate or leave them alone when each version has a legitimate purpose.
Links and Authority Terms
Backlink, Link Building and Anchor Text
A backlink is a link from another website to yours. Link building is the work of earning or attracting relevant external links through useful resources, digital PR, partnerships, outreach or other legitimate editorial reasons. The number of links alone is a weak quality test; relevance, editorial context and the source itself matter.
Anchor text is the clickable text inside a link. Descriptive anchor text gives a reader useful context before they click. Exact-match, partial-match, branded and generic anchors are descriptive labels used by SEO practitioners, not separate Google scores.
Normal Links, Nofollow, Sponsored and UGC
Dofollow is an informal SEO term for a normal link without a qualifying rel value such as nofollow. Google’s current guidance says ordinary links that it should fetch and parse do not need a rel attribute. Paid placements should use rel="sponsored"; user-generated links can use rel="ugc"; nofollow is appropriate when the other values do not apply and the publisher would rather Google not associate the site with, or crawl the linked page from, that link. Google’s outbound link guidance is the current reference.
Example of a nofollow link:
Example of a normal link without a nofollow attribute:
Domain Authority and Page Authority
Domain Authority (DA) and Page Authority (PA) are Moz metrics that estimate the relative ranking strength of a domain or page using Moz’s data and models. They are not Google metrics, and a higher score does not prove that a particular link is useful or that a page will rank. Use third-party authority scores as comparison inputs, then check relevance, real visibility, editorial quality and the page itself. Moz’s ranking and visibility resource defines both metrics.
Analytics and SEO Reporting Terms
Impression, Click and CTR
In Google Search Console, an impression is recorded when a search result is shown under Google’s counting rules, and a click is generally recorded when the user clicks through to a page outside the Google search surface. CTR is clicks divided by impressions. The exact counting rules vary by result type, so Search Console metrics should be interpreted using Google’s own methodology rather than treated as generic web analytics numbers. Google’s Search Console metric definitions explain the details.
CTR formula:
A low CTR is not automatically a title problem. Position, query intent, search features, brand recognition and the type of result can all change the likelihood of a click.
Google Analytics 4, Events and Bounce Rate
Google Analytics 4 (GA4) measures user interactions through events. Events can include page views, clicks, scrolls, purchases and other actions depending on the implementation. GA4 data answers a different question from Search Console: Search Console measures how a site appears and is clicked in Google Search, while GA4 measures activity after users reach the site or app.
In GA4, bounce rate is the percentage of sessions that were not engaged sessions. An engaged session lasts longer than 10 seconds, contains a key event or has at least two page or screen views. Because a visitor can get a complete answer and leave, bounce rate should not be treated as a universal quality score. Google Analytics documentation on engagement and bounce rate gives the current definition.
Organic Traffic, Paid Traffic and Conversion
Organic traffic comes from unpaid search results. Paid traffic comes from advertising placements. The distinction describes acquisition, not quality: either channel can send useful or poor-fit visitors depending on the campaign, query and landing page.
A conversion is a defined action that matters to the organisation, such as a purchase, qualified enquiry, booking or sign-up. Conversion rate compares completed conversions with the relevant traffic or user base under the measurement method being used. SEO reporting is stronger when search visibility is connected to meaningful outcomes rather than reduced to rankings alone.
How to Use This Glossary During an SEO Audit
When a report says a page has an ‘SEO problem’, replace the broad label with the term that describes the actual failure. That small change usually makes the next action much clearer.
- Start with access: Can the priority URL be discovered and crawled?
- Check indexability: Is the intended canonical page eligible for indexing, and are canonical or noindex signals conflicting?
- Check the search task: Does the page type and content match the query and search intent?
- Check search appearance: Are the title, snippet, structured data and SERP context being interpreted correctly?
- Check measurement: Separate Search Console visibility metrics from GA4 on-site behaviour and business conversions.
If a term in an audit cannot be tied to a specific mechanism, measurement or decision, ask for the explanation before acting on it. Jargon is not evidence.
