Definition of "onager" [‖On•a•ger]

• A fast-running wild ass (Equus hemionus subsp. onager) of central Asia, having an erect mane and a broad black stripe along its back. (noun)
• An ancient and medieval stone-propelling siege engine. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The wild ass is called onager because "ass" in Greek is onus and "wild" is agrion."
• "The onager is a wild ass that brays 12 times to signal the spring equinox."
• "The Kulan, or onager (Equus hemionus onager), is an endangered subspecies of Asian wild ass which has been recently introduced in this ecoregion (Kapchagai preserve) from Turkmenistan, where the only remaining wild population lives in the Badghyz Reserve."