acetone (CH3COCH3), also called 2-propanone or dimethyl ketone, organic solvent of industrial and chemical significance, the simplest and most important of the aliphatic (fat-derived) ketones. Acetone is a chemical used to make products like nail polish remover and paint remover. Your body also makes this chemical when it breaks down fat. Acetone is safe in normal amounts, but too much of it could be a problem.