Strong's #1512: gachown (pronounced gaw-khone')
 probably from 1518; the external abdomen, belly (as the source of the faetus (compare 1521)):--belly.
Brown-Driver-Briggs Hebrew Lexicon:
 ּ 
  gâchôn 
 
 1) belly (of reptiles)
 
  Part of Speech: noun masculine
Relation: probably from H1518
Usage:
This word is used 2 times:
Genesis 3:14: "and above every beast of the field; upon  thy belly shalt thou go, and dust"
Leviticus 11:42: "Whatsoever goeth upon  the belly, and whatsoever goeth upon all four,"