Compounds containing the carbonyl group, C=O. The term is commonly used in the restricted sense of aldehydes and ketones, although it actually includes carboxylic acids and derivatives.
See also: oxo compounds
Metal carbonyls, in which carbon monoxide is a formal ligand.
Source: PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1325 (https://doi.org/10.1351/pac199567081307)