ˈasə̇l, -ˌsēl noun
( -s )
Etymology: International Scientific Vocabulary ac id + -yl; probably originally formed as German azyl
: a radical derived usually from an organic acid by removal of the hydroxyl from all acid groups ; especially : a radical (as benzoyl, adipoyl) derived from a carboxylic acid and having the general formula RCO— in the case of a monobasic acid
acyl halides
— compare acyloxy