Meta Description

A meta description is the short summary of a web page that search engines often show beneath its title in the results, to tell searchers what the page is about. It does not directly change your ranking, but a clear, inviting one can persuade more people to click your result over another.

It is like the blurb on the back of a book: it does not change what is inside, but it decides whether someone picks it up. A meta description matters because two sites can rank side by side, and the one whose summary better answers the searcher's need tends to win the click.