To this day, if you type the word orc into Microsoft Word, it'll come up as a misspelling. But any LOTR fan could tell you that the word is as real as balrog, for goodness' sake! Popularized by J.R.R. Tolkien in The Hobbit, orc has remained a part of popular culture since. However, when he created his demonic species, Tolkien drew from the Latin word Orcus, one of the Latin nicknames for the Roman version of Hades, the god of the dead. Meanwhile, another Lord of the Rings species, the ogre, also drew its origin from Orcus, with a stop at its French homonym. Two ghoulish creatures, both from the ultimate monster. Makes sense. But where does Orcus come from? The origin is unknown and largely obscure, but several theories have been put forth. Some think it's from the Byzantine word Ogur, which meant "Hungarian", but as cool as that would be, it's probably not right. Others trace it to the Greek god Horkos, the lord of oaths, a noun from horkos, "oath" and eventually PIE serk, "to fence". Whatever; it's interesting nonetheless.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd