Ketones may be classified according to the type of hydrocarbon group present in their molecules, including aliphatic ketones, alicyclic ketones, aromatic ketones, saturated ketones, and unsaturated ketones. Among these, aliphatic ketones contain open-chain aliphatic hydrocarbon groups; alicyclic ketones feature a carbonyl group attached to a cyclic aliphatic hydrocarbon; and aromatic ketones possess at least one aromatic ring connected to the carbonyl group. Furthermore, based on degree of saturation, ketones can be subdivided into saturated and unsaturated ketones.

Additionally, ketones may be categorised as monocarbonyl compounds, dicarbonyl compounds, or polycarbonyl compounds based on the number of carbonyl groups present in the molecule. Among monocarbonyl compounds, if the two hydrocarbon groups attached to the carbonyl group are identical, they are termed symmetrical ketones (or monoketones), such as acetone; if the two hydrocarbon groups differ, they are termed mixed ketones, such as phenylacetone.
 

Industrially, acetone and similar compounds serve as highly effective cleaning agents and paint thinners, while also functioning as crucial organic synthesis intermediates. They are extensively utilised in the production of steroid hormones, epoxy resins, and other polymeric materials.  
Within the flavour and fragrance industry, numerous ketone compounds are highly valued for their distinctive and agreeable aromas. For instance, raspberry ketone possesses a rich berry aroma and is a key component in natural fruit flavourings. Aliphatic asymmetric ketones containing 7 to 12 carbon atoms (such as methyl nonyl ketone and methyl heptenone) typically exhibit strong, long-lasting fragrances and can be used directly in synthetic perfumes. Among aromatic ketones, compounds like phenylacetone and p-methylphenylacetone possess refined floral notes, frequently utilised in perfumes, cosmetics, and personal care products.