from
The Collaborative International Dictionary of English v.0.48
Narwhal \Nar"whal\ (n[aum]r"hw[.a]l), n. [Sw. or Dan. narvhal;
akin to Icel. n[=a]hvalr, and E. whale. the first syllable is
perh. from Icel. n[=a]r corpse, dead body, in allusion to the
whitish color its skin. See {Whale}.] [Written also
{narwhale} and {narwal}.] (Zool.)
An arctic cetacean ({Monodon monocerous}), about twenty feet
long. The male usually has one long, twisted, pointed canine
tooth, or tusk, projecting forward from the upper jaw like a
horn, whence it is called also {sea unicorn}, {unicorn fish},
and {unicorn whale}. Sometimes two horns are developed, side
by side.
[1913 Webster]