$N$-Hydrocarbyl derivatives of the parent structure $\ce{HN^{+}(O^{−})(OH)2}$. Cf. phosphonic acids.
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1321 [Terms] [Paper]