Of a plane figure: having the form of a pentagon; five-sided. Also: of or relating to a pentagon or pentagons.

Having five angles and five straight sides; five-cornered or five-sided; = pentagonal, adj.

Having five sides.

Having five angles or corners; pentagonal; = quinquangular, adj. Obsolete. rare.

= pentagonal, adj. Obsolete. rare.

pentagonal; = quinquangular, adj.

Having five angles or corners; pentagonal. Also figurative.

Having five angles or angular points; pentagonal.

Used to form nouns and adjectives with the sense ‘relating to, consisting of, or having five (of the thing specified)’, as quintagenarian, quintopoly…

Having five sides.

Resembling a pentagon, somewhat pentagonal; (Physical Anthropology) denoting a skull having a roughly pentagonal cross-section when viewed from above.