LATIN DICTIONARYLexicon Latīnum
proper noun · masculinesecond declension

Pēgasus1

Pēgasus m sg (genitive Pēgasī)
Classical[ˈpeː.ɡa.sʊs]Ecclesiastical[ˈpɛː.ɡa.s̬us]

Meaning

  1. GreekPegasus
  2. A Roman cognomen — famously held by
  3. Plotius Pegasus (a Roman senator and jurisconsult active under the Flavian dynasty)

Declension

declension
formsingularplural
nominativePēgasus—
genitivePēgasī—
dativePēgasō—
accusativePēgasum—
ablativePēgasō—
vocativePēgase—

Pēgăsus (-os), i, m., = Πήγασος,
I. the winged horse of the Muses, who sprang from the blood of Medusa when she was slain, and with a blow of his hoof caused the fountain of the Muses (Hippocrene) to spring from Mount Helicon. Bellerophon afterwards caught him at the fountain of Pirene, near Corinth, and, with the aid of his hoofs, destroyed the Chimœra. But when Bellerophon wished to fly on the back of Pegasus to heaven, the latter threw him off and ascended to the skies alone, where he was changed into a constellation, Ov. M. 4, 785; 5, 262 sq.; id. F. 3, 458: ales, Hor. C. 4, 11, 27; Hyg. Fab. 151; id. Astr. 2, 18.—Applied in jest to a swift messenger, Cic. Quint. 25, 80. —Of winged horses in gen., Plin. 8, 21, 30, § 72; cf.: sunt mirae aves cornutae (in Africā) et equinis auribus Pegasi, Mel. 3, 9.— Hence,
1. Pēgăsēïus, a, um, adj., Pegasean, i. e. poetic: melos, Pers. praef. 14. —
2. Pēgăsĕus (Pēgăsēus, Mart. Cap. 9 fin.), a, um, adj., of or belonging to Pegasus, Pegasean: volatus, Cat. 55, 24: habenae, Claud. in Ruf. 3, 262: aquae, Hippocrene, id. Epigr. 5, 4.—Pegaseum stagnum, a lake in lonia, Plin. 5, 27, 31, § 115: aetas Pegaseo corripiet gradu, i. e. with rapid step, Sen. Troad. 385.—
3. Pēgă-sis, ĭdis, f. adj., of Pegasus: Pegasides undae, the waters of Hippocrene, the fountain of the Muses, Ov. Tr. 3, 7, 15: unda, Mart. 9, 59, 6.—Subst.: Pēgăsĭdes, the Muses, Ov. H. 15, 27; Prop. 3 (4), 1, 19.—Pēgă-sis, ĭdis, f., = Πήγή, a fountain-nymph: Pegasis Oenone Phrygiis celeberrima silvis, Ov. H. 5, 3.

Origins

Borrowed from Ancient Greek Πήγασος (Pḗgasos).

In the Academy Smith's classical dictionaries

Biography & mythologyPegasusPegasus. 2. The famous winged horse, whose origin is thus related. When Perseus struck off the head of Medusa, with whom Poseidon had had intercourse …
noun · masculinesecond declension
pēgasus2
pēgasus m (genitive pēgasī)
Classical[ˈpeː.ɡa.sʊs]Ecclesiastical[ˈpɛː.ɡa.s̬us]

Meaning

  1. pegasus (a winged horse or a bird with a horse's head, suspected to live in Africa)
    Sunt mirae aves cornutae tragopanes et equinis auribus pegasi.[In Africa] there are wonderful birds: horned tragopans and pegasi with horse's ears.c. 45 CE, Pomponius Mela, De situ orbis libri III 3
    Aethiopia generat […] pinnatos equos et cornibus armatos, quos pegasos vocant. 1855 translation by John Bostock and Henry Thomas Riley Æthiopia produces […] horses with wings, and armed with horns, which are called pegasi.77 CE – 79 CE, Plinius Maior, Naturalis Historia 8.72

Declension

declension
formsingularplural
nominativepēgasuspēgasī
genitivepēgasīpēgasōrum
dativepēgasōpēgasīs
accusativepēgasumpēgasōs
ablativepēgasōpēgasīs
vocativepēgasepēgasī

Pēgăsus, i, m.,
I. a celebrated jurist in the reign of the emperor Vespasian, Dig. 1, 2, 2, § 47; Juv. 4, 77.—Hence,
B. Pē-găsĭānus, a, um, adj., Pegasian: senatus consultum, Just. Inst. 2, tit. 23.

Origins

Borrowed from Ancient Greek Πήγασος (Pḗgasos).

Quick answers

What does Pēgasus mean in Latin?
Pēgasus, a proper noun, means “Pegasus; A Roman cognomen — famously held by”.
What is the genitive of Pēgasus?
The genitive singular is Pēgasī. Pēgasus is masculine, second declension.
How do you pronounce Pēgasus?
In classical Latin, [ˈpeː.ɡa.sʊs]; in ecclesiastical (church) Latin, [ˈpɛː.ɡa.s̬us].