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.
(click for a larger image)dodecagon
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.