Keywords are words and phrases people type into search engines to search for something online. In other words, keywords act as a channel to connect your website with the intended audience.
For example, if you were looking to buy a new blazer, you might type something like “men’s casual blazers” into Google. Even though that phrase consists of more than one word, it’s still a keyword.
Source:https://turboanchor.com/keyword-density-how-it-affects-seo/