Fundamentals: a search term - also known as a query - are the actual searches that your advert showed for. Each search term/query is matched to a keyword. The same search terms can be triggered by multiple keywords. About the search terms report

You want to find keywords that have sufficient impressions, with conversion and positive click metrics.

Avoid adding low search volume keywords with less than 1 impression per day. A low volume keyword can actually reduce the chance of your ad triggering.

Let close-variants collect low volume searches instead.