Pronunciation: (un'dur-bel"ē), [key]
1. the lower abdomen; posterior ventral area, as of an animal's body.
2. the lower surface of an object; underside: the underbelly of an airplane.
3. a vulnerable area; weak point: an attack on the soft underbelly of Europe.
4. a dark, seamy, often hidden area or side: a police officer continually exposed to the underbelly of society.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.