Septagon vs. Heptagon

Septagonnoun

(proscribed) A polygon with seven sides and seven angles.

Heptagonnoun

(geometry) A polygon with seven sides and seven angles.

Heptagonnoun

A plane figure consisting of seven sides and having seven angles.

Heptagonnoun

a seven-sided polygon

Heptagonnoun

a plane figure with seven straight sides and angles.

Heptagon

In geometry, a heptagon is a seven-sided polygon or 7-gon. The heptagon is sometimes referred to as the septagon, using (an elision of septua-, a Latin-derived numerical prefix, rather than hepta-, a Greek-derived numerical prefix; both are cognate) together with the Greek suffix meaning angle.