Cyclops, meaning "round-eyed" or "circle-eyed" refers to a race of ancient one-eyed giants.
Various poets have described cyclopes, including Homer, Euripides, Theocritus, Virgil, and Hesiod. Hesiod wrote that they were the offspring of Gaia and Uranus, while Homer told of shepherd cyclopes who were the sons of Poseidon, the sea god. Cyclopes were the workmen of Hephaestus, the god of blacksmiths, sculptors, and volcanoes.
The most well-known cyclops was the giant Polyphemus, who encountered the soldier Odysseus and his men during their epic journey home to Ithaca. Odysseus's men were trapped in the cave of the shepherd Polyphemus, and are only able to escape by blinding Polyphemus's single eye. Odysseus had previously told Polyphemus that his name was "Nobody", so when the giant shouts to his brothers that "Nobody" has blinded him, they believe he has been struck blind by the gods and do not come to his aid. The men of Odysseus then tie themselves to the underside of Polyphemus's sheep so that the blind cyclops does not feel them with his hands as he lets his sheep out to graze.
Though Odysseus escapes, he makes the mistake of revealing his true name to Polyphemus, who begs his father Poseidon to curse Odysseus. This leads to many challenges for the rest of the soldier's long journey.
It is believed that ancient Greeks may have based the cyclops on prehistoric elephant skulls, which have tusks and a large hole in the center of the head. Though in reality this hole is where the trunk attaches, it may have been mistakenly perceived as an eye socket.