SEO Glossary: Link Building and Technical SEO Terms

Few fields hide as much meaning behind three-letter abbreviations as search marketing. An invoice says "DR 55," a publisher asks whether a link is "dofollow," and an audit mentions "canonical conflicts," all in the same week. This SEO glossary collects the terms you will meet most often, with short definitions, a note on where each one is commonly misread, and a pointer to a deeper guide where one exists. It suits buyers placing their first order, publishers fielding pitches, and newcomers on an agency team.

The terms are grouped into nine topics: links, metrics, crawling, content, technical setup, measurement, advertising, link risk and AI search. Definitions stay deliberately brief, and no single term is explored at length here. One caution applies throughout: scores such as DR, DA, PA and spam score come from third-party tools, depend on each tool's own scale and data, and are not values Google uses. Where that matters, the note is repeated.

Link Terms: Backlink, Dofollow, Nofollow, Sponsored, UGC and Anchor

Links are the backbone of the web and of this vocabulary. Google's SEO Starter Guide explains that most sites are found automatically, mainly through links from pages Google has already crawled. The words below are the everyday names for the pieces of that system.

• Backlink: a link from another website to one of your pages. For the full concept, see what is a backlink.
• Outbound link: a link from your site to a different site.
• Internal link: a link from one page of your site to another page of the same site.
• Dofollow: informal shorthand for a normal link with no special attribute. It is not an official attribute value.
• Nofollow: a rel value. In Google's documentation it is the fallback when the other values do not apply.
• Sponsored: a rel value for advertisements and paid placements.
• UGC: a rel value for links inside user-generated content such as comments and forum posts.
• Referring domain: a distinct domain that links to you at least once. A hundred links from one site still count as one referring domain.
• Link profile: the full set of links pointing at a site, including sources, link text and spread.

How the four rel choices work in practice is covered in dofollow vs nofollow vs sponsored vs UGC links. Google's guidance on qualifying outbound links states a clear preference for the sponsored value on paid placements, which is why that value matters for both buyers and publishers.

Metric Terms: DR, DA, PA and Spam Score

Everything in this group is calculated by a third-party tool. Two tools can disagree about the same site, and none of them shows how Google evaluates it. Treat these numbers as a way to compare options, not as a forecast of results.

• DR (Domain Rating): Ahrefs' score for the link strength of a domain. It is tool-specific and not a Google value.
• DA (Domain Authority): Moz's predictive score for a domain. Its scale and method belong to Moz and differ from DR. The gap between them is explained in domain authority vs domain rating.
• PA (Page Authority): the same idea applied to a single page instead of a whole domain.
• Spam score: Moz's indicator of how many risk signals a site shares with sites that were penalized. It is tool-specific and is not a penalty. See what is spam score for the details.
• Keyword difficulty (KD): a tool's estimate of how hard it is to rank for a query, calculated differently by each provider.
• Estimated organic traffic: a projection built from ranking and search volume data, not a count of real visits.
• PageRank: the link-based signal associated with Google's early ranking system. Do not confuse it with tool scores.

A practical habit: whenever someone quotes a number, ask which tool produced it, how its scale works and when it was last refreshed.

Crawling and Indexing Terms

A page can only appear in search results if it is first discovered, then crawled, then indexed. These terms describe those steps and the files that influence them.

• Crawling: automated programs visiting pages and reading their content.
• Googlebot: the general name for Google's crawling software.
• Indexing: storing a crawled page in the search engine's database. Not every crawled page is indexed.
• Robots.txt: a file at the root of a site that tells crawlers which paths they may fetch. It controls crawling, not removal from the index.
• Noindex: a meta tag or HTTP header value asking that the page stay out of the index.
• XML sitemap: a file listing important URLs. It helps discovery but does not promise indexing.
• Crawl budget: a rough description of how many resources a crawler spends on a site, relevant mainly for very large sites.
• Orphan page: a page that no other page on the site links to.

The common thread is simple: when a page cannot be found, cannot be crawled, or is told to stay out of the index, even excellent content will not show up in results.

Content Terms: E-E-A-T, Topical Authority and Search Intent

Content vocabulary mixes official Google concepts with industry slang. Separating the two prevents a lot of confusion.

• E-E-A-T: experience, expertise, authoritativeness and trustworthiness. It is a framework from Google's quality guidance, not a single score you can read off a dashboard.
• Search intent: what the person behind a query is really trying to do: learn, compare, buy or reach a specific site.
• Topical authority: an industry term for the impression that a site covers a subject deeply and consistently. Google does not publish it as a metric.
• Keyword: the phrase people type into a search box; the starting point of most content plans.
• Long-tail keyword: a longer, more specific query that usually has lower volume.
• Thin content: shallow pages that add little original value for a reader.
• Pillar page or hub: a broad overview that links out to detailed pages on subtopics. This glossary works the same way.
• Cannibalization: several pages on one site competing for the same intent.

None of these is a magic switch. They all point to the same goal: answer the visitor's question accurately and completely.

Technical Terms: Canonical, hreflang and Redirects

Most technical terms exist to resolve confusion when the same content lives at several addresses or in several languages. Google's starter guide describes how search engines pick one preferred version of duplicated content and call it the canonical URL.

• Canonical: the rel=canonical link element that names the preferred address. It is a hint, not a command. Typical mistakes are covered in canonical tag issues, audit and fixes.
• Hreflang: markup that connects language or regional versions of the same content.
• 301 redirect: signals a permanent move.
• 302 redirect: signals a temporary move.
• 404: the status code for a page that cannot be found.
• Core Web Vitals: user experience measures for loading, interactivity and visual stability.
• Structured data (schema markup): markup that labels page content in a form machines can read.
• Mobile-first indexing: indexing that relies mainly on the mobile version of a page.

The classic technical misunderstanding is treating a hint as an order. Canonical and hreflang are the usual examples.

Measurement Terms: CTR, Impressions and ROI

Measurement vocabulary tells you whether the work is paying off. You will meet most of these words in Search Console and analytics reports.

• Impression: one appearance of a result in front of a searcher.
• Click: a visit from a result to your page.
• CTR (click-through rate): clicks divided by impressions.
• Average position: where a page appeared on average in the results.
• Organic traffic: visits coming from unpaid search results.
• Conversion: a predefined goal being completed, such as a purchase, form or signup.
• KPI: the key indicator chosen to judge a project.
• ROI (return on investment): the relationship between the value gained and the resources spent.
• Search Console: Google's free tool for performance and index reporting.

Which indicators suit a link campaign is discussed in backlink campaign KPIs: which metrics matter, and one way to estimate return is shown in how to measure backlink ROI.

Advertising and Publisher Terms: CPM, CPC and ads.txt

When a site earns revenue as well as traffic, advertising language comes into play. These abbreviations appear in publisher dashboards and ad agreements.

• CPM: cost or revenue per thousand impressions.
• CPC: cost or revenue per click.
• RPM: revenue per thousand page views; the exact definition can vary by platform.
• Fill rate: the share of ad slots that actually received an ad.
• Viewability: whether an ad had a chance to be seen in the visible part of the screen.
• ads.txt: a text file at the site root where a publisher lists the companies authorized to sell its ad inventory.
• Sponsored content: material published for payment that should be disclosed to readers.
• Media kit: a publisher's presentation of audience, formats and terms.

Definitions here can differ slightly between platforms and contracts. When reading a revenue report, rely on the help page of the platform that produced it.

Link Risk Terms: PBN, Disavow and Negative SEO

These are the words buyers and publishers ask about when they worry about risk. Only definitions appear here; the deeper judgment lives in the linked guides.

• PBN (private blog network): a group of sites, often controlled by one owner, that link to each other to influence rankings. It is generally described as conflicting with Google's spam policies.
• Link scheme: the umbrella name for buying and selling links in order to manipulate rankings.
• Disavow: a file and tool used to suggest Google ignore specific links. Most sites do not need it as a routine task.
• Negative SEO: the claim that someone is deliberately trying to harm a competitor's search presence.
• Link spam: low-quality links dropped through comments, forums or mass automation.
• White hat: methods that follow search engine guidelines.
• Black hat: manipulative methods that break those guidelines.
• Manual action: a corrective measure applied by Google's reviewers and reported in Search Console.

To judge which side of the line a tactic falls on, read white hat vs black hat link building. For questions about link text, anchor text strategy for link profiles is the better start. Anchor text is the clickable wording of a link, and Google's starter guide says it helps both users and search engines understand what the linked page contains.

AI Search Terms: GEO and Entities

As AI-assisted search surfaces spread, new labels have appeared. Many are marketing shorthand rather than official definitions, so read them with care.

• GEO (generative engine optimization): an industry label for efforts to make content more likely to be cited in generative answers. There is no standard definition.
• AEO (answer engine optimization): a similar label for preparing content that suits direct-answer surfaces.
• Entity: a distinct thing that search systems can recognize, such as a person, brand, place or concept.
• AI Overviews: the name Google uses for the AI-generated summaries it shows for some searches.
• Citation: a page shown as a source inside an AI-generated answer.

The key principle: new labels do not replace old foundations. Accurate, clear and trustworthy content is still the common denominator.

A Quick Reference Table for Core SEO Glossary Terms

The table below gathers the most commonly confused terms in one place. Each line is only a reminder; return to the matching section above for context.

Keep it open before an order or a call. For any row whose meaning you cannot recall at once, the section above holds the longer explanation.

Sample Template: Personal SEO Glossary Notes Table

Reading definitions is only the first half of learning them. Writing down where each term shows up in your own work makes it stick. Picture a hypothetical case: a small recipe blogger who has just received a first partnership offer jots down the unfamiliar words in a table like the one below. The rows only illustrate the layout and do not describe a real site or any outcome.

Fill the last column honestly. Rows marked "Partly" become next week's reading list. After a few months, the table gives you a clear picture of which terms you now use comfortably and which still raise questions.

Frequently Asked Questions

Where can you learn SEO terms?

Start with primary sources such as Google Search Central's starter guide, then read the help pages of the tool providers whose scores you use. Keeping a notes table where you restate each term in your own words and record its source makes the vocabulary far easier to retain than memorizing a list.

What is the difference between dofollow and nofollow?

Dofollow is an informal name for a normal link without a special attribute, not an official value. Nofollow is a rel value defined in Google's documentation. Paid links have their own sponsored value, and user-generated content has the ugc value, so the choice depends on the link's origin.

Are DR and DA the same metric?

No. DR is calculated by Ahrefs and DA by Moz, each with its own method, data sources and refresh schedule. Both are tool-specific and neither is a value Google uses. It is normal to see different numbers for the same site, so compare within one tool.

Why does anchor text matter?

According to Google's starter guide, link text tells users and search engines what the linked page is about. Descriptive wording helps people decide whether to click and helps systems understand the destination. Vague wording such as "click here" gives neither group much information.

What do PBN and disavow mean?

A PBN is a private network of sites built to influence rankings, generally treated as conflicting with Google's spam policies. Disavow is a tool for suggesting that Google ignore specific links. It is not a routine task for most sites and should be used with care.

How often do glossary terms change?

Core concepts stay stable for years, while tool scores, AI search labels and platform interfaces change more often. When unsure, check the current version of the relevant official page and add a date to your own notes so you know how fresh a definition is.

Conclusion and Next Step

Knowing a word is only useful when you also know which decision it supports. Use the distinctions in this glossary as filters: tool score or Google documentation, hint or rule, estimate or measured result. Those three questions clear up most of the confusion buyers and publishers run into.

Once the vocabulary feels familiar and you are ready to plan a first link project, compare the options on the backlink packages page. You pick a package and add it to your cart, complete the payment, and follow seller approval and the delivery notice inside the order flow. If a delivery does not match what you expected, the dispute path sits in the same flow.