十边形,十角形
Decagon \Dec"a*gon\, n. [Pref. deca- + Gr. ? a corner or angle: cf. F. d['e]cagone.] (Geom.) A plane figure having ten sides and ten angles; any figure having ten angles. A regular decagon is one that has all its sides and angles equal.
decagon n : a polygon with 10 sides and 10 angles