Tertiarium, rij, n. g. Cato. A thirdendeale: a tierce.Tertiata verba.Wordes vnperfltely pronounced for feare, as they doe that being in feare of him to whome they speake, scantly vtter euerie third worde.
Tertiárius, Adiect. Of the third sort. vt Tertiarium stannum. Plin.
Lewis and Short: Latin dictionary
tertĭārĭus, a, um, adj. [id.], 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.