1. [n]  the underpart of the body of certain vertebrates such as snakes or fish
2. [n]  a protruding abdomen
3. [n]  the region of the body of a vertebrate between the thorax and the pelvis
4. [n]  the hollow inside of something; "in the belly of the ship"
5. [n]  a part that bulges deeply; "the belly of a sail"
6. [v]  swell out or bulge out

1. \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.
   
   

2. \Bel"ly\, v. t. [imp. & p. p. {Bellied}; p. pr. & vb. n.
   {Bellying}.]
   To cause to swell out; to fill. [R.]
   
         Your breath of full consent bellied his sails. --Shak.
   
   

3. \Bel"ly\, v. i.
   To swell and become protuberant, like the belly; to bulge.
   
         The bellying canvas strutted with the gale. --Dryden.
   
   

the seat of the carnal affections (Titus 1:12; Phil. 3:19; Rom. 16:18). The word is used symbolically for the heart (Prov. 18:8; 20:27; 22:18, marg.). The "belly of hell" signifies the grave or underworld (Jonah 2:2).