An acyl group is a functional group that is characterized by a carbonyl group attached to an alkyl or aryl group. There are several synonyms for the term acyl group, including carbonyl group, ketone group, aldehyde group, and formyl group. These terms are often used interchangeably, depending on the context in which they are being used. The acyl group is an important functional group in organic chemistry, frequently found in compounds like carboxylic acids, esters, anhydrides, and amides. Understanding the terms and their synonyms is therefore crucial in understanding the properties and reactions of such compounds and their derivatives.