Answer
Definition (Ketone): A carbonyl group with two alkyl groups attached.
Example: Propan-2-one $CH_3-CO-CH_3$
Work Step by Step
Definition: The carbonyl group, C=O, is the functional group for both aldehydes and ketones. A ketone has two alkyl groups bonded to the carbonyl group. Ketone names generally have the -one suffix. The general formula is R-CO-R'
Example: Propan-2-one $CH_3-CO-CH_3$