Ŏc'ta-gŏn, n.

n. [Gr. ὀκτάγωνος, eight-cornered, from ὀκτώ, eight, and γωνία, corner; Fr. octogone, Sp. octagono, It. ottagono.] (Geom.) A plane figure of eight sides and eight angles.

Regular octagon, one in which the sides are all equal, and the angles also are all equal.