This prefix is now rejected. It has been used in the past, especially in cyclic systems, to name carbenes, e.g. 'carbenacycloheptane', now cycloheptylidene.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1324 (https://doi.org/10.1351/pac199567081307)