Pentagon

UK: ˈpentəɡən | US: ˈpentəɡɑːn

Definition
  1. n. a polygon with five sides and five angles

  2. n. (proper noun) the headquarters of the US Department of Defense, named for its five-sided shape

Structure
penta <five>gon <angle>
Etymology

pentagon = penta<five> + gon<angle>

  • penta: From Greek pente (five), used in English as a combining form (e.g., pentagram, pentathlon).
  • gon: From Greek gōnia (angle or corner), commonly seen in geometric terms (e.g., polygon, hexagon).

Etymology Origin:
The word "pentagon" directly reflects its geometric meaning, combining Greek penta (five) and gon (angle). This logical construction mirrors other shape-related terms in mathematics (e.g., "hexagon," "octagon"). The US Department of Defense adopted the name for its iconic five-sided building, reinforcing the word’s association with structure and symmetry.

Examples
  1. A regular pentagon has five equal sides and angles.

  2. The Pentagon is one of the world’s largest office buildings.

  3. She drew a perfect pentagon on her geometry worksheet.

  4. The architect incorporated a pentagon-shaped courtyard into the design.

  5. The symbol featured a red pentagon on a white background.