In Greek mythology, the Olympians were the major deities who Ancient Greeks believed in. The Olympians were twelve and comprised of Zeus, Hera, Poseidon, Demeter, Athena, Apollo, Artemis, Ares, Aphrodite, Hephaestus, Hermes and either Hestia or Dionysus. Their name, Olympians, originates from Mount Olympus, which was their place of residence; therefore, although sometimes Hades and Persephone were included in the Olympians, they should be excluded in the sense that they lived in the underworld.

Source: https://www.greekmythology.com/Olympians/olympians.html