| Noun | 1. | acyl group - any group or radical of the form RCO- where R is an organic group; "an example of the acyl group is the acetyl group" acetyl, acetyl group, acetyl radical, ethanoyl group, ethanoyl radical - the organic group of acetic acid (CH3CO-) chemical group, radical, group - (chemistry) two or more atoms bound together as a single unit and forming part of a molecule foryml - (chemistry) the negative univalent acyl radical CHO that occurs in aldehydes |