Decagon
/ˈdɛk.ə.ɡɒn/noun
A polygon with ten sides and ten angles.
Did you know?The same Greek root behind *decagon* also powers words like *decade* and *December*, because in older Roman calendars ten was a sacred counting number before the year was expanded.
Etymological Timeline
Ancient Greek
Greek
deka-
“ten”
Ancient Greek
Greek
gōnia
“angle, corner”
Late Latin
Latin
decagonum
“ten-angled figure”
16th Century
English
decagon
“a ten-sided polygon”
Modern English
English
decagon
“a polygon with ten sides and ten angles”