‘Keyword research’ is the process of identifying the search terms which should be most productive to target for your SEO or search advertising efforts. And one of the simplest tools in ‘keyword research’ is starting to type the term into Google.
As you do so, you are of course offered ‘autocomplete’ suggestions by Google. These are influenced heavily by how often the terms are typed in, so they’re a good pointer towards terms you should be thinking about. However, they are initially only terms which start with the letters you have typed so far:
Note though that if you complete the search, and move on to another word, you can get suggestions which contain your original term, not necessarily starting with it. I’ve found many good ideas this way.