What is the purpose of keyword in SEO?

Keyword is a word or group of words that makes a phrase that is being typed by the person in search box of the search engine.

These keywords are used by search engines to populate the subjects over the Internet and search results are populated according to that.

Search engines stores the keywords in the database for the web sites and when the search is being it picks the most matched word from the database.

The words can be found out or placed in the order for the web site that displays them in order of preference.

Keywords are also written in the Meta tag that is placed in tag and it describes the website.