narwhal
NAR-wul
The unicorn of the sea — a medium-sized Arctic whale whose males grow a single spiraling tusk up to ten feet long. The tusk is actually a canine tooth, threaded with nerve endings, possibly a sensory organ for reading the water. Medieval Europeans believed the tusks were unicorn horns.
Etymology
Old Norse: nárhvalr, possibly from nár (corpse) + hvalr (whale) — for the animal's mottled grey skin resembling a drowned body. Or from nár (narrow) referring to the tusk.
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