We don't have synonyms for pegasos yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are pegasus, petasos and pegasys.
(n) :
Alternative form of Pegasus. [(Greek mythology) A winged horse fabled to have sprung from the blood of Medusa when she was slain. He is noted for causing, with a blow of his hoof, Hippocrene, the inspiring fountain of the Muses, to spring from Mount Helicon. Bellerophon tamed and rode upon Pegasus when he defeated the Chimaera.]
(n) :
Alternative form of Pegasus. [(Greek mythology) A winged horse fabled to have sprung from the blood of Medusa when she was slain. He is noted for causing, with a blow of his hoof, Hippocrene, the inspiring fountain of the Muses, to spring from Mount Helicon. Bellerophon tamed and rode upon Pegasus when he defeated the Chimaera.]