a. rare. [f. L. trīgēsim-us thirtieth + -AL.] † a. Thirtieth. Obs. b. loosely. Consisting of thirty (i.e., in quot., days).
1637. Saltonstall, Eusebius’ Constantine, 141. The trigesimall yeare of his raigne.
1839. Fraser’s Mag., Aug., 203/1. The upper part may originally have been a crescent, implying monthly…. The figure thus connects itself with the monthly trigesimal period.
