SERP
Search Engine Results Page
The SERP is the page a search engine displays in response to a query: organic results, ads, enhanced snippets.
A modern SERP goes well beyond ten blue links: it mixes paid ads, a featured snippet, People Also Ask, local results, and increasingly an AI-generated answer at the top of the page.
Studying a keyword's SERP before writing a page reveals what Google judges relevant for that query, and therefore which content format has the best odds of ranking there.