| Decagon (n.) A plane figure having ten sides and ten angles; any figure having ten angles. A regular decagon is one that has all its sides and angles equal. Thesaurus Entries Big Dick, Decalogue, Ten Commandments, X, abundant year, academic year, annum, bissextile year, calendar month, calendar year, century, common year, day, decagon, decagram, decahedron, decaliter, decameter, decare, decastere, decastyle, decasyllable, decemvir, decemvirate, decennary, decennium, decigram, deciliter, decimeter, decurion, defective year, fiscal year, fortnight, hour, leap year, lunar month, lunar year, lunation, luster, lustrum, man-hour, microsecond, millennium, millisecond, minute, moment, month, moon, quarter, quinquennium, regular year, second, semester, session, sidereal year, solar year, sun, ten, tenner, term, trimester, twelvemonth, week, weekday, year |