nitrenes

Synonym: aminylenes
https://doi.org/10.1351/goldbook.N04145
  1. The neutral compound HN: having univalent nitrogen, and its derivatives RN. Aminylenes is a recognized but less widely used synonym. Other names that have been used include aminediyls, imidogens, azenes. They may exist in either a singlet or a triplet electronic state (four spin-paired electrons, or two spin-paired and two with parallel spins, respectively), e.g. CH3N: methylnitrene.
  2. Until the 1960s, nitrenes had a totally different meaning: analogues of nitrones in which the double-bonded oxygen is replaced by double-bonded carbon, thus azomethine ylides.
Sources:
PAC, 1993, 65, 1357. 'Revised nomenclature for radicals, ions, radical ions and related species (IUPAC Recommendations 1993)' on page 1357 (https://doi.org/10.1351/pac199365061357)
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1350 (https://doi.org/10.1351/pac199567081307)
See also:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1145 [Terms] [Paper]