Adjective
Pertaining to a decagon; having ten sides.
Source: Webster's dictionaryThe first type, polygonal (dihedral) quasicrystals, have an axis of 8, 10, or 12-fold local symmetry (octagonal, decagonal, or dodecagonal quasicrystals, respectively). Source: Internet
The round, aluminium bronze dollar coin was replaced in 1989 with a decagonal, cupro-nickel type. Source: Internet
The diagram at the right shows the high-gain antenna (HGA) with a 3.7 m diameter dish attached to the hollow decagonal electronics container. Source: Internet