The pods of the tropical African acacia Acacia nilotica, used in tanning and dyeing.
Origin
Mid 19th century; earliest use found in Andrew Ure (1778–1857), chemist. From a language of Senegal; compare Noon nebneb, nepnep, Serer nebneb, nèfnèf, nepnep, Wolof nèbnèb, nèpnèp.