hydroxybenzoic acid

noun

hy·​droxy·​ben·​zo·​ic acid -ben-ˌzō-ik- 

: any of three crystalline derivatives C₇H₆O₃ of benzoic acid that contain one hydroxyl group per molecule: as

a

: the colorless para-substituted acid used in making several of its esters that are effective preservatives

called also parahydroxybenzoic acid

b

: salicylic acid