A commonly used but undesirable term for azo imides (Should not be confused with 'azimino', the name for the bridging group,
–N=N–NH–).
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1321 (https://doi.org/10.1351/pac199567081307)