Illustrated Glossary of Organic Chemistry

Nitranion: A contraction of nitrogen anion. Any atom, group, or molecule with a nitrogen atom having two lone pairs and a negative formal charge. By a quirk in IUPAC nomenclature, a nitranion that is the conjugate base of ammonia or an amine is called an amide, despite the lack of a carbonyl group.

Conjugate base of ammonia
Lithium diisopropylamide
Conjugate base of acetamide
Representative nitranions.