trĕcentēsĭmus, a, um, adj. [trecenti],
the three-hundredth : annus, Cic. Rep. 1, 16, 25; Liv. 4, 7, 1; Val. Max. 8, 13 fin. ; Eutr. 2, 1.
trecentēsimus adj. trecenti, the three-hundredth : annus, L. ...
An Elementary Latin Dictionary