SERP stands for Search Engine Results Page, which in Portuguese means "Results Page".
SERP is a technical term to represent pages that display results in an Internet search.
SERP’s vary according to the searched keywords, and are usually composed of natural results that appear on the left side of the search. By default, each SERP is a maximum of ten results per page.
Typically, SERPs are presented in the following structure: title of webpage with link, two lines with a brief description about the content of that page or related text the keyword, and a last line with options such as page cache, alternate version, or Translation.
SERP is one of the main search engines on Google, Yahoo!, Bing and others, and can include many types of lists: contextual, algorithmic or organic search, as well as sponsored links, images, maps, definitions, videos and etc.
webmasters use Search Engine Optimization (SEO) to increase your ranking on sites with a certain keyword, and as a result, webmasters often check SERP’s to track their search progress.
See also the meaning of IF THE and WITHOUT.