The phrase "match keywords" means finding words or phrases that are similar or related to the specific words you are searching for or trying to match. Full definition
In reality, the results are not that different from broad match keywords that you set up, but the slight change does help to focus better on your intended target audience. (searchmarketingstandard.com)
Fill your ad groups with exact match keywords only, and you'll miss out on huge volumes of traffic. (entrepreneur.com)
Instead of matching keywords in queries, its new strategy is to manage more complex queries by attempting to understand the meanings and relationships of words and concepts. (entrepreneur.com)