bimestrial,a.|baɪˈmɛstrɪəl| [f. L. bimestri-s (f.bi- two + mensis month) + -al1.] Of two months' duration; occurring every two months. 1846Worcester cites Q. Rev.1870Lowell Among my Bks.Ser. ii. (1873) 11 An office which the Florentines had made bimestrial in its tenure.