The Collaborative International Dictionary of English v.0.48:
Hexagon \Hex"a*gon\, n. [L. hexagonum, Gr. ? six-cornered; "e`x six (akin to E. six) + ? angle.] (Geom.) A plane figure of six angles. [1913 Webster] Regular hexagon, a hexagon in which the angles are all equal, and the sides are also all equal. [1913 Webster]WordNet (r) 3.0 (2006):
regular hexagon n 1: a hexagon with six sides of equal length