Definition of "crupper" [crup•per]

• A leather strap looped under a horse's tail and attached to a harness or saddle to keep it from slipping forward. (noun)
• The rump of a horse; the croup. (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.

• "Perched behind him on the crupper was a cheetah, a gilded collar around its neck, a chain of silver links running between it and the groom's hand."
• "All the arguments which I have heard adduced against the doctrine here laid down would also go to prove that a horse cannot fall which has a bearing-rein and a crupper, that is, whose head is tied to his tail."
• "His back is less straight, and there is a dip behind the withers and a rounding of the crupper which is more like the shape of the horse; his neck also is more erect and arched than that of the ass."