tertĭārĭus, a, um, adj. [tertius], containing a third part.
I Adj. : stannum, that contains one part of white and two of black lead , Plin. 34, 17, 48, § 160. —
II Subst.: tertĭārĭum , ii, n., a third part , a third , Cato R. R. 95, 1; Vitr. 4, 7, 5.