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.

nar-wayl A small Arctic whale, Monodon monoceros, the male of which has a long straight spirally twisted tusk developed from one of its teeth.

small arctic whale the male having a long spiral ivory tusk