(1):

(n.) A winged horse fabled to have sprung from the body 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. On this account he is, in modern times, associated with the Muses, and with ideas of poetic inspiration.

(2):

(n.) A northen constellation near the vernal equinoctial point. Its three brightest stars, with the brightest star of Andromeda, form the square of Pegasus.

(3):

(n.) A genus of small fishes, having large pectoral fins, and the body covered with hard, bony plates. Several species are known from the East Indies and China.