the constellation Pegasus.
Before X Was X: The Dark Horse Story Of The 24th LetterSince its inception, the letter X has struggled to establish its own identity, so it may be no coincidence that X is commonly used to represent the unknown in both language and mathematics. But, how was it created?
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for winged horse
The rock that brought Sindbad across, The Calendar's own winged-horse!East and West: Poems|Bret Harte