TER'TIATE, verb transitive [Latin tertius, third; tertio, to do every third day.] 1. To do any thing the third time. 2. To examine the thickness of the metal at the muzzle of a gun; or in general, to examine the thickness to ascertain the strength of ordnance.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI