A search term — also called a query — is the exact word or phrase a person types or speaks into a search engine. It is the raw input straight from the user, which makes it distinct from a keyword: the term a marketer deliberately targets and optimises for.
The two are easy to confuse but sit on opposite sides of the screen. The search term is what the user actually enters; the keyword is what you choose to build a page around. One keyword can catch hundreds of different search terms. If you optimise for the keyword "running shoes," real people reach you by typing "lightweight running shoes for marathon," "cheap running shoes size 11," and "are Hoka running shoes good for knees." Google Ads and Search Console both expose a search-terms report so you can see the messy reality behind your tidy keyword list.
The wording of a term signals what the searcher wants. "Running shoes" is broad and ambiguous; "buy Nike Pegasus 41 size 10" is transactional and ready to convert; "why do my running shoes squeak" is informational. Matching a page to that user intent matters more than the raw phrase — and mining search-term reports for high-intent variations is where much practical keyword research value hides.