Pegasus is a legendary winged horse in Greek mythology that was sired by the ocean god Poseidon and birthed by the gorgon Medusa when she was slain by the Perseus. Greco-Roman poets write about his ascent to heaven and how Zeus instructed him to bring lightning and thunder from Olympus. Pegasus is the creator of Hippocrene, the fountain on Mt. Helicon.

He was captured by Bellerophon with the help of Athena and Poseidon. Pegasus allows the hero to ride him to defeat a monster, the Chimera, before going on to many other exploits. After his rider fell off his back trying to reach Mount Olympus, Zeus transformed him into the constellation Pegasus.

The name Pegasus is also been popularised in many forms of media, from movies to television shows, many of which feature numerous species of winged horses referred to as a pegasus or pegasi.