TertiateTer"ti*ate\, v. t. [L. tertiatus, p. p. of tertiare to do for the third time, fr. tertius the third.]1. To do or perform for the third time. [Obs. & R.] --Johnson. 2. (Gun.) To examine, as the thickness of the metal at the muzzle of a gun; or, in general, to examine the thickness of, as ordnance, in order to ascertain its strength.