What is "belly fretting"

Belly \Bel"ly\ (b[e^]l"l[y^]), n.; pl. Bellies (-l[i^]z). [OE. bali, bely, AS. belg, b[ae]lg, b[ae]lig, bag, bellows, belly; akin to Icel. belgr bag, bellows, Sw. b["a]lg, Dan. b[ae]lg, D. & G. balg, cf. W. bol the paunch or belly, dim. boly, Ir. bolg. Cf. Bellows, Follicle, Fool, Bilge.]

1. That part of the human body which extends downward from the breast to the thighs, and contains the bowels, or intestines; the abdomen.

   Note: Formerly all the splanchnic or visceral cavities were called bellies; -- the lower belly being the abdomen; the middle belly, the thorax; and the upper belly, the head.
   --Dunglison.

2. The under part of the body of animals, corresponding to the human belly.

   Underneath the belly of their steeds.
   --Shak.

3. The womb. [Obs.]

   Before I formed thee in the belly I knew thee.
   --Jer. i. 5.

4. The part of anything which resembles the human belly in protuberance or in cavity; the innermost part; as, the belly of a flask, muscle, sail, ship.

   Out of the belly of hell cried I.
   --Jonah ii. 2.

5. (Arch.) The hollow part of a curved or bent timber, the convex part of which is the back.

   Belly doublet, a doublet of the 16th century, hanging down so as to cover the belly.
   --Shak.

   Belly fretting, the chafing of a horse's belly with a girth.
   --Johnson.

   Belly timber, food. [Ludicrous]
   --Prior.

   Belly worm, a worm that breeds or lives in the belly (stomach or intestines).
   --Johnson.