Definition of "haunch"

But I had no time to pursue these reflections; for the gray horse came to the door, and made me a sign to follow him into the third room where I saw a very comely mare, together with a colt and foal, sitting on their haunches upon mats of straw, not unartfully made, and perfectly neat and clean.

1726 October 28, [Jonathan Swift], Travels into Several Remote Nations of the World. […] [Gulliver’s Travels], volume II, London: […] Benj[amin] Motte, […], part IV (A Voyage to the Houyhnhnms)

And the rabbit from his path-wayLeaped aside, and at a distanceSat erect upon his haunches.

1855 November 10, Henry Wadsworth Longfellow, “chapter III”, in The Song of Hiawatha, Boston, Mass.: Ticknor and Fields

While Heracles, - the thews and cordage of his thighsStraitened and strained beyond the utmost stretchFrom quivering heel to haunch like sweating hawsers.

1916, Wilfred Owen, The Wrestlers

The fog comes on little cat feet.It sits looking over harbor and cityon silent haunches and then moves on.

c. 1918, Carl Sandburg, Fog

He [Novak Djokovic] dropped to his haunches just inside the baseline as Centre Court rose to acclaim the champion, hugging South African [Kevin] Anderson at the net before skipping over towards his box and celebrating wildly in front of his coaching team and wife Jelena.

2018 July 15, Jonathan Jurejko, “Novak Djokovic Wins Fourth Wimbledon by Beating Kevin Anderson”, in BBC Sport‎, archived from the original on 14 February 2019

Now these are the Laws of the Jungle, and many and mighty are they; / But the head and the hoof of the Law and the haunch and the hump is—Obey!

1895 November, Rudyard Kipling, “The Law of the Jungle”, in The Second Jungle Book, London, New York, N.Y.: Macmillan and Co., page 25

On the rough-hewn oaken table the venison haunch was shared.

a. 1892, John Greenleaf Whittier, The Garrison of Cape Ann