hydrocarbylidene groups

https://doi.org/10.1351/goldbook.H02892
Divalent groups, R2C=, formed by removing two hydrogen atoms from the same carbon atom of a @[email protected], the free valencies of which are engaged in a double bond.
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1341 [Terms] [Paper]