AKA Pterigotippus
In Greek mythology, 'pterippus' (plural, pterippi) was the name for any winged horse with the ability to fly. The pterippi are all descended from Pegasus and Euippe. Pegasus was the original winged horse, who sprung forth fully-formed from Medusa's blood when Perseus decapitated Medusa. He married Euippe (or, some say, her sister Ocyrrhoe), who was the daughter of the centaur Chiron, and they had two children, Celeris and Melanippe. Exactly how the rest of the pterippi were produced, history does not relate; however it can be assumed that having wings proved to be a dominant trait, while having a human torso did not.
These days a winged horse is more likely to be called a pegasus (plural, pegasi). This is technically incorrect; Pegasus could be considered a pterippi himself, but he was only the one individual.
Related beasts include the hippolepididopterus or papillequine, pterocentaur, pyrippus, and hippogriff. Other winged horses are Alborak (a.k.a. Boraq or Burak), Alsvidur, Arvakur, and Mamoun.