pendecagonrare.|pɛnˈdɛkəgən| [Short for *pentedecagon, f.Gr. πέντε five + δέκα ten + -γωνος -angled.] A plane figure having fifteen angles and fifteen sides: = quindecagon. 1695W. Alingham Geom.Epit. 95 It is also necessary to inscribe a pentagone in a Circle, as also a pendecagone.