homogentisic acid

noun

ho·​mo·​gen·​tis·​ic acid ˌhō-mō-ˌjen-ˈtiz-ik, ˌhäm-ō- 

: a crystalline acid C₈H₈O₄ formed as an intermediate in the metabolism of phenylalanine and tyrosine and found especially in the urine of those affected with alkaptonuria