https://doi.org/10.1351/goldbook.I02960
This term systematically means carbenes bearing an imino or N-substituted imino group, RN=, somewhere in the molecule. E.g. R–C:–CH2C(=NR)R. It is listed here in order to warn against its misuse for alkylideneamino carbenes.
See: carbenes, nitrile ylides