Definition
SERP stands for search engine results page — the page a search engine displays after you type in a query and hit enter. It is what most people simply call “the Google results.” A modern SERP is far more than ten blue links. It can include paid ads at the top, a local map pack, featured snippets (answer boxes), image carousels, “People also ask” sections, video results, and organic listings. The layout varies depending on the type of query.
Why It Matters
Your position on the SERP determines how much search traffic your website receives. The top three organic results capture the vast majority of clicks, and anything below the fold — let alone on page two — is effectively invisible to most searchers. But position is only part of the picture. The type of SERP features that appear for your target keywords affects your strategy. If Google shows a featured snippet for a question you are targeting, winning that snippet can leap you above the traditional number-one result. If the SERP is dominated by ads and a map pack, organic results are pushed further down and the battle shifts. Understanding what the SERP looks like for your keywords shapes how you approach your SEO.
Example
A financial adviser targets the keyword “how much do I need to retire.” The SERP for that query shows a featured snippet, a “People also ask” section, and three ads before any traditional organic results. Knowing this, they structure their content to directly answer the question in a format Google favours for featured snippets, and they win the snippet — appearing at the very top of the page above all standard results.