Late 19th century; earliest use found in Isaac Funk (1839–1912), publisher and reformer. From scientific Latin Pegasus, genus name + -id, after scientific Latin Pegasidae, family name.
Definition of pegasid in US English:
pegasid
nounˈpɛɡəsɪd
Zoology
A fish of the family Pegasidae; a sea-moth.
adjectiveˈpɛɡəsɪd
Zoology
Of or relating to the family Pegasidae.
Origin
Late 19th century; earliest use found in Isaac Funk (1839–1912), publisher and reformer. From scientific Latin Pegasus, genus name + -id, after scientific Latin Pegasidae, family name.