(n.) A figure or polygon bounded by twelve sides and containing twelve angles.
Example Sentences:
(1) New findings on quasicrystals with icosahedral, octagonal, decagonal, and dodecagonal symmetries obtained recently in the Beijing Laboratory of Electron Microscopy, Chinese Academy of Sciences, are presented.
(2) The old pound coin, as we must soon call it, was too simple to reproduce; a dodecagon represents a whole new challenge.