narwhal
Concise Oxford English Dictionary © 2008 Oxford University Press:
narwhal /ˈnɑːw(ə)l/
▶noun a small Arctic whale, the male of which has a long forward-pointing spirally twisted tusk developed from one of its teeth. [Monodon monoceros.]
– origin C17: from Du. narwal, Dan. narhval, based on ON nár ‘corpse’, with ref. to skin colour.
'narwhal' also found in these Oxford entries:

