Definition: Polyphemus was the son of Poseidon and the nymph Thoosa. He was the one-eyed giant Cyclops famous from the Odyssey, who imprisoned Odysseus and his men in a cave. Since Polyphemus was eating Odysseus' men, Odysseus was under some pressure to figure a way out, which he did. Odysseus tricked Polyphemus, poked out his eye, and got his remaining men out of the cave and into safety. As punishment for hurting his son, Poseidon made Odysseus suffer on his way home to Ithaca after the Trojan War.