For cyclic ketones, numbering starts from the end nearer to the carbonyl group. The carbonyl carbon is assigned position one in the naming of cyclic ketones.

IUPAC names of aldehydes and ketones are derived from alkanes by replacing “-e” with “-al” and “-one,” respectively. The longest carbon chain is numbered starting from the aldehyde or ketone carbon, and substituents are prefixed alphabetically with position numbers.

Some ketones have historical common names, the simplest dimethyl ketone is called acetone. Alkyl phenyl ketones are usually named by adding the name of acyl group as prefix to the word phenone.

Common names of ketones involve naming two alkyl or aryl groups bonded to the carbonyl group. Greek letters (α, α’, β, β’, etc.) indicate the locations of substituents, starting with the carbon atoms next to the carbonyl group.

Common names of aldehydes are derived from corresponding carboxylic acids by replacing “-ic” with “aldehyde.” They often reflect the original source of the acid and indicate the location of substituents with Greek letters.