A polygon with ten sides and ten angles.
[Medieval Latin decagōnum, from Greek dekagōnon, from neuter of dekagōnos, having ten angles : deka, ten; see dek in the Appendix of Indo-European roots + -gōnos, angled; see -GON.]
de·cago·nal (dĭ-kăgə-nəl) adj.
(click for a larger image)decagon
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