Match types allow Amazon sellers to fine-tune which shopper search terms their ads may be eligible to be shown against. Sellers can choose from broad, phrase, and exact match types.
Broad match keywords will give the most traffic exposure, while phrase and exact match will restrict traffic to a more precise target audience.
There’s another match type that gives Amazon sellers that last little bit of control over which search terms trigger keywords in a sponsored products campaign.
It’s called a Negative Keyword and it can be used in either exact or phrase match types. Adding negative keywords tells Amazon that you do not want to connect to those search terms even if they match one of your keywords.