Webster's Revised Unabridged Dictionary · 1913

Octagon

Octagon , noun

[Greek {not transcribed} eight-cornered; 'okta- (for 'oktw` eight) + {not transcribed} an angle: compare French cctogone.]

1.
(Geometry) A plane figure of eight sides and eight angles.
2.
Any structure (as a fortification) or place with eight sides or angles.
Collocations (1)
Regular octagon , one in which the sides are all equal, and the angles also are all equal.