pentagon

Meanings

1. 1
   noun

   A polygon with five sides and five angles.

   Imagine a vast sheet of paper on which straight Lines, Triangles, Squares, Pentagons, Hexagons, and other figures, instead of remaining fixed in their places, move freely about, […]

2. 2
   name

   The United States Department of Defense.

   The Vietnamese people inspired youth of all nationalities […] by demonstrating that the determination of a people to fight for their sovereignty and right to self-determination was an unconquerable force, even in the face of Pentagon might.

3. 3
   noun

   a five-sided polygon

4. 4
   noun

   A fort with five bastions.

5. 5
   name

   The headquarters of the United States Department of Defense.

Etymology

From Middle French pentagone, from Late Latin pentagōnum, from Ancient Greek πεντάγωνον (pentágōnon), noun use of the neuter of the adjective πεντάγωνος (pentágōnos, “five-angled”), from πέντε (pénte, “five”) + -γωνος (-gōnos, “angled”). Equivalent to penta- + -gon.