Phenolic acid in the context of "Polyphenol"

Polyphenols (/ˌpɒliˈfiːnoʊl, -nɒl/) are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.