aldehydes

https://doi.org/10.1351/goldbook.A00208
Compounds RC(=O)H, in which a carbonyl group is bonded to one hydrogen atom and to one R group.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1312 (https://doi.org/10.1351/pac199567081307)