— pentagonal /pen tag"euh nl/ , adj. — pentagonally , adv.
/pen"teuh gon'/ , n.
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.
[ 1560-70; pentagonum pentágonon, n. use of neut. of pentágonos five-angled. See PENTA-, -GON ]