'acyl' originates from the German word 'Acyl,' which is derived from the Latin word 'acidus,' meaning 'sour' or 'acid.'

'Acyl' was adopted into English from the German term 'Acyl,' which itself was derived from the Latin 'acidus.'

Initially, it referred to a sour or acidic property, but over time it evolved to denote a specific group in organic chemistry.