a. [TRI- 3.] a. Occurring every three months. b. Lasting or extending over three months.
1869. J. D. Burns, Mem. & Rem., vi. 104. Our trimonthly Communion.
1870. Cornh. Mag., July, 66. The trimonthly homes of country squires.
1879. Daily News, 1 Dec., 6/5. Annual as opposed to bi-monthly or tri-monthly budgets.
