A Keyword is a word used to perform a search on a search engine.
Technically any word could be a Keyword. The easiest way to explain it is, a word that people put into the search bar to try and find the bit of information they need.
If I wanted to know about dogs, I would type dogs into the search bar. That would make Dog the Keyword. If I wanted to know about being more eco-friendly on the web I may search ‘How can I be greener on the web’ and in this instance greener and web would be my key words.
Keywords are extremely important when it comes to creating sites and the content you put on them. Finding out what Keywords people are searching for and adding them into you site will increase your chances of you site ranking higher on the search page.