do·dec·a·gon 
(dō-dĕkə-gŏn′)
(dō-dĕkə-gŏn′)n.
A polygon with 12 sides and 12 angles.
[Greek dōdekagōnon : dōdeka, twelve (duo, two; see dwo- in the Appendix of Indo-European roots + deka, ten; see dek in the Appendix of Indo-European roots) + -gōnon, -gon.]
do′de·cago·nal (dō′dĕ-kăgə-nəl) adj.
dodecagon