DictionarypentagonUnited States defense department
proper noun

pentagon

The United States Department of Defense and its senior military leadership.

The Pentagon reviews plans to send more troops overseas.

Etymology

Pentagon means a five-angled figure. The Department of Defense acquired the building’s name because its headquarters has that five-sided shape.

More examples

  • Congress asks the Pentagon to explain its spending.
  • A Pentagon spokesperson answers questions about the mission.
  • The White House consults the Pentagon before announcing the deployment.

Forms

Pentagon

Similar words

Department of Defense
Names the department directly rather than through its headquarters.
military leadership
Refers to senior commanders, not the entire defense department.