benzoyl /ˈbɛnzəʊ.ɪl/ noun[in compounds]1 •A univalent radical formally derived from benzoic acid, C₆H₅CO-, by removal of the hydroxyl group.The O–O bond in benzoyl peroxide and the C–N bonds in AIBN homolyze under thermal or photochemical conditions. — 2007 formsbenzoyls