Noah Webster
Monodon
MON'ODON, noun [Gr. having one tooth or shoot.] The unicorn fish, or sea-unicorn, which has a remarkable horn projecting from its head. [This horn is really a tusk, of which there are two, but only one of them is usually developed.]
It is called also the monoceros, or horned narwhal. Its usual size is form sixteen to twenty feet.