八边形,八角形,八角堂
Octagon \Oc"ta*gon\, n. [Gr. ? eight-cornered; ? (for ? eight) + ? an angle: cf.F. cctogone.] 1. (Geom.) A plane figure of eight sides and eight angles. 2. Any structure (as a fortification) or place with eight sides or angles. {Regular octagon}, one in which the sides are all equal, and the angles also are all equal.
octagon n : an eight-sided polygon