What does "belly" mean?

Belly: The under part of the body of animals, corresponding to the human belly. Underneath the belly of their steeds. Shak.

Additional senses

  1. 2.The womb. [Obs.] Before I formed thee in the belly I knew thee. Jer. i.
  2. 3.4. 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.
  3. 4.5. (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.
  4. 5.To cause to swell out; to fill. [R.] Your breath of full consent bellied his sails. Shak.
  5. 6.To swell and become protuberant, like the belly; to bulge. The bellying canvas strutted with the gale. Dryden.

Sources