- monoceros (n.)
- c. 1300, "the unicorn," from Old French monoceros "unicorn," from Latin monoceros, from Greek monokeros, from mono- "single" (see mono-) + keras "horn of an animal," from PIE *ker- (1) "horn, head" (see horn (n.)).
This is a modern constellation, generally supposed to have been first charted by Bartschius as Unicornu; but Olbers and Ideler say that it was of much earlier formation, the latter quoting allusions to it, in the work of 1564, as "the other Horse south of the Twins and the Crab"; and Scaliger found it on a Persian sphere. [Richard Hinckley Allen, "Star Names and Their Meanings," London: 1899]
Probably it owes its origin to Flemish cartographer Petrus Plancius in the 1590s.