What Is a Keyword in SEO?
A keyword in SEO is a word or phrase people type or speak into a search engine, used as the unit for researching demand, planning pages, and measuring rankings. A keyword stands for a need: the topic someone wants to know about and the reason they are searching. Search engines no longer require the exact words of a query to appear on a page. Google’s SEO starter guide explains that “Google’s language matching systems are sophisticated and can understand how your page relates to many queries, even if you don’t explicitly use the exact terms in them.”
Keyword and Query
A query is the exact string a person enters. A keyword is the term you research and target to stand for a group of related queries, such as “running shoes” for “best running shoes,” “running shoes for women,” and “where to buy running shoes.” The queries in a group need not share its exact words, since search engines match meaning as well as wording. Research tools and rank trackers work with keywords; Search Console shows the actual queries.
Types of Keywords by Search Volume
| Type | Typical form | Search volume | Example |
|---|---|---|---|
| Head term | A broad term | High | shoes |
| Mid-tail | A narrower term | Moderate | women's running shoes |
| Long-tail | A specific or uncommon phrasing | Low for each phrase, large in total | best running shoes for flat feet |
There is no official cutoff between these groups. Search volume places a query among them; word count is a common trait, not the test, and a short query can sit in the tail. Head terms are broad and can mean several things. A narrow long-tail term makes the intent clearer, though low volume does not by itself mean low competition.
Types of Keywords by Intent
A more useful grouping is by what the searcher wants. In his 2002 paper “A Taxonomy of Web Search”, Andrei Broder divided web queries into three classes: navigational, to reach a particular site; informational, to find information; and transactional, to perform an action such as a purchase or download. SEO practice adds a fourth label, commercial investigation, for searches that compare options before buying. It is not part of Broder’s taxonomy, but comparison searches behave differently from both pure research and a purchase.
| Intent | Example |
|---|---|
| Informational | what is a keyword |
| Navigational | Google Search Console login |
| Commercial investigation | best keyword research tools |
| Transactional | Semrush pricing |
A page built to answer an informational search does not satisfy a transactional one just because it contains the same words. Matching the intent matters more than matching the phrase.
How Search Moved Beyond Matching Words
Google’s language systems changed what a keyword has to do.
- BERT. Google’s 2019 announcement explained that BERT considers the full context of a word, including small words such as “to” and “for,” and that it would “help Search better understand one in 10 searches in the U.S. in English.”
- MUM. Announcing it on May 18, 2021, Google described MUM as “1,000 times more powerful than BERT,” “trained across 75 different languages,” and multimodal, “so it understands information across text and images.”
None of this made keywords irrelevant. A page still has to make its subject clear, but it does not need to repeat a phrase in a fixed order or at a fixed frequency to be associated with it.
Keywords on the Page
- Name the main topic in the title element and the H1.
- Use the term and its natural variations in headings and text where they read naturally.
- Write descriptive URLs and alt text.
- Cover the topic well enough that related terms appear without being forced.
Repetition has a limit. Google’s spam policies treat keyword stuffing, filling a page with keywords in an unnatural way to manipulate rankings, as spam.
Keywords and Paid Search
Advertisers pay more per click for keywords close to a purchase, which is why keyword value is discussed in terms of ad prices. As an illustration only: a keyword costing $50 per click, with 5% of clicks turning into $2,000 sales, returns $100 in revenue per click, twice its cost. Real costs and conversion rates vary by industry and location; take figures from your own ad account, not from a quoted average.
Starting Keyword Research
Begin with a few seed terms that describe the business’s core topics, then expand them with Search Console, which shows the queries already bringing impressions; Google Trends, which shows interest over time; and keyword databases such as Ahrefs or Semrush. Group the results by intent before volume.
Keywords and AI Features
Google’s documentation on AI features explains that AI Overviews and AI Mode can run related searches across subtopics, a technique Google calls query fan-out, and that a page must be indexed and able to show with a snippet in Google Search to appear as a supporting link. Keyword research for these features means finding the questions behind long queries, not guessing exact wording.
Questions About Keywords
How many keywords should one page target?
One primary topic per page. A page that covers its topic well can rank for many related terms; a page split between several unrelated topics gives each of them less.
What is keyword cannibalization?
Two or more pages on one site competing for the same keyword and intent in a way that hurts results, for example when the wrong page ranks. Two pages touching one topic is not enough to show it; confirm the loss in Search Console before merging, and keep pages that serve different needs.