Originally: †a genus of carnivorous marine gastropods of the family Nassariidae which includes some dog whelks (obsolete: see note). Subsequently also: a genus of marine gastropods of the family Muricidae. Also (occasionally with lower-case initial): a mollusc of either of these genera; (also, in "nassa shell") the shell of such a mollusc.
Valid publication of the (current) genus name: P. F. Röding Museum Boltenianum (1798) ii. 132. This preoccupies Nassa Lamarck 1799, which is therefore taxonomically invalid and has been replaced by Nassarius.
Mid 19th century; earliest use found in Henry McMurtrie (1793–1865). From scientific Latin Nassa from classical Latin nassa basket fish-trap (further etymology uncertain).