Pronunciation: (pen'tu-gon"), [key]
1. a polygon having five angles and five sides.
2. the Pentagon,
a. a building in Arlington, Virginia, having a plan in the form of a regular pentagon, containing most U.S. Defense Department offices.
b. the U.S. Department of Defense; the U.S. military establishment.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.