It's A Weird Word

 I learned this from Mental Floss:

In Latin, larva originally meant “ghost” or “ghoul,” and when the word first began to be used in English in the mid-1600s, it meant precisely that. But because the ghosts and ghouls of antiquity were often portrayed as wearing a disguise to hide amongst the world of the living, in Latin larva also came to mean “mask,” and it was this figurative sense that the 18th century naturalist Carl Linnaeus meant when he began to call the juvenile forms of insects larvae in the 1700s.

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