A keyword may refer to any of the following:
1. With a search function, a keyword is a word or group of words that help the search locate a better match for their search. In the past, search engines relied off meta tags to get the keywords of a page. Today, search engines grab the full page and then use algorithms to determine what keywords describe the page.
2. Keyword was also a term used with AOL (America Online) when searching for a specific site.