bel·ly (b?l??)n. pl. bel·lies 1. See abdomen.2. The underside of the body of certain vertebrate animals, such as a snake.3. A cut of meat from the underside of an animal, especially a pig.4. Informal a. The stomach.b. An appetite for food.5. The womb; the uterus.6. a. A part that bulges or protrudes: the belly of a sail.b. Anatomy The bulging, central part of a muscle.7. A deep or central interior space: the engine in the belly of a ship; fish down in the belly of a river.intr. & tr.v. bel·lied, bel·ly·ing, bel·lies To bulge or cause to bulge. See Synonyms at bulge.Phrasal Verb: belly up To approach closely: belly up to the bar.[Middle English beli, from Old English belg, bag; see bhelgh- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.bel?lied (?b?l id) adj. having a belly big-bellied. [1425?75] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.