n. 五角形, 五边形

[经] 五角平台

Pentagon \Pen"ta*gon\, n. [Gr. ?; ? (see {Penta-}) + gwni`a
angle: cf. L. pentagonium, F. pentagone.] (Geom.)
A plane figure having five angles, and, consequently, five
sides; any figure having five angles.

{Regular pentagon}, a pentagon in which the angles are all
equal, and the sides all equal.