Pentagon
/ˈpɛn.tə.ɡɒn/noun
A five-sided polygon or, in general use, a building or headquarters associated with the U.S. Department of Defense.
Did you know?Its root comes from Greek *pente* (“five”), the same ancient number behind words like *pentagram* and *pentathlon*, where five wasn’t just math — it was symbolic power.
Etymological Timeline
Proto-Indo-European
PIE
*penkʷe
“five”
Ancient Greek
Greek
pénte
“five”
Ancient Greek
Greek
gōnía
“angle, corner”
Late Latin
Latin
pentagonum
“five-angled figure”
Middle French
French
pentagone
“pentagon”
Modern English
English
pentagon
“a five-sided polygon”
Explore more surprising origins