I.quinquangular, pentagonal.— Subst.: pentăgōnĭum , i, n., a pentagon (post-class.): pentagonii ratio, Auct. de Limit. p. 257 Goes.—pentăgōnum , i, n., for pentaphyllon, App. Herb. 2.
pentăgōnĭus , a, um, adj., = πενταγώνιος and pentăgōnus , a, um, = πεντάγωνος,