Keywords are words or phrases that are used to match ads with the terms people are searching for. The keyword match types dictate how closely the keyword needs to match with the user’s search query so that the ad can be considered for the auction.
Google Ads Keyword Match Types: https://support.google.com/google-ads/answer/7478529
Amazon Ads Keyword Match Types: https://sellermetrics.app/amazon-ppc-match-types