När'wal or När'whal, n.

n. [Written also narwhale.] [Sw. & Dan. narhvall, Icel. nāhvalr, Fr. narval, from A. S. hwāl, Icel. hvalr, Eng. whale, and Icel. nār, nā, corpse, dead body, on account of the whitish color of its skin, or from nar, for A. S. nasu, the nose, or contracted from Greenland. a-nar-nak, a kind of narwhal.] (Ichth.) A cetaceous mammal (Monodon monoceros), found in the northern seas, which grows to twenty feet in length. The male has usually one long, twisted tusk, projecting forward from the upper jaw like a horn. From this circumstance it is called also sea-unicorn, unicorn-fish, or unicorn-whale.