# pentagon

/ˈpɛnɪˌɡɑn/ (US) · /pˈɛntəɡən/ (UK)

Source: https://englishreference.com/word/pentagon
Updated: 2026-08-15

## Senses

### 1. geometric shape

noun · CEFR B2

a flat shape that has five straight sides and five angles.

For teachers: a polygon with five sides and five interior angles.

- The children learned how to draw a perfect pentagon in their geometry class.
- The architect incorporated a regular pentagon into the floor plan to create a unique flow between the five main galleries.

### 2. U.S. military headquarters

noun · CEFR B2 · American English

the large five-sided building near Washington, D.C., where the U.S. Department of Defense is located.

For teachers: the headquarters building of the United States Department of Defense, located in Arlington, Virginia.

- He was promoted to a new position at the Pentagon last year.
- Security around the Pentagon was significantly increased following the announcement of the new defense protocols.

### 3. U.S. military leadership

noun · CEFR C1 · Academic · American English

the people who lead the U.S. military and make defense decisions.

For teachers: a metonym for the leadership and administrative authority of the United States Department of Defense.

- The Pentagon announced a new plan to support international peace efforts.
- Political analysts spent the week debating whether the Pentagon would approve the proposed budget cuts for the next fiscal year.

Usage: Usually used with 'the' and capitalized.

## Examples

- The Pentagon announced a new plan for national security.
- Journalists waited outside the Pentagon for a statement regarding the recent changes in military strategy.
- While the building itself is a marvel of mid-century architecture, the Pentagon is more frequently discussed in political science as the central hub of American global strategic planning.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.