The nitrogen-centered radical $\ce{H2N^{.}}$, formally derived by the removal of a hydrogen atom from ammonia, and its hydrocarbyl derivatives $\ce{R2N^{.}}$.
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1317 [Terms] [Paper]