A keyword is, the important part of a content. In terms of SEO, a keyword is a particular word or phrase that sums up the entire content on a web page. Search engines, such as Google, use these keywords to match appropriate web pages with search queries entered by users.
For example, a web page about headphones might use a keyword, such as ‘best over ear headphones 2016’. Or an online furniture store might target keywords such as ‘buy furniture cheap online’.
Basically keyword(s) is the name for a meta elements (it is concatenated because HTML name attribute cannot contain a space.
For content the phrase should be “key word”, where ‘key’ is used as a synonym for “important” which we can as well say Important words in a Content .
We can also have different definitions from different Scholars in the Internet world .