a. A fabled creature symbolic of virginity and usually represented as a horse with a single straight spiraled horn projecting from its forehead.
b. Heraldry A representation of this beast, having a horse's body, a stag's legs, a lion's tail, and a straight spiral horn growing from its forehead, especially employed as a supporter for the Royal Arms of Great Britain or of Scotland.
2. Unicorn The constellation Monoceros.
a. Something that is greatly desired but difficult or impossible to find: “Is antigravity the unicorn of physics? Or do we simply lack the strategy and bait to catch it in an experimental snare?” (Jerome Groopman).
b. Business A startup company valued at one billion dollars or more.
[Middle English unicorne, from Old French, from Late Latin ūnicornis, from Latin, having one horn : ūnus, one; see oi-no- in the Appendix of Indo-European roots + cornū, horn; see ker-1 in the Appendix of Indo-European roots.]
(click for a larger image)unicorn
The Lady and the Unicorn: "Sight,"one in a series of six 15th-century tapestries
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus