a. and adv. [TRI- 3.]
A. adj. a. Occurring every three weeks, or lasting for three weeks. b. Usually, Occurring, appearing, or operating three times every week.
1817. Mississippi Republican, 28 May, 3/4. heading, A new tri-weekly Paper at the seat of government.
1832. (May 17) W. T. Barry, in Amer. State Papers (1834), XV. 348. The line of stages connecting Philadelphia and Delaware with the Eastern shore of Maryland and Virginia, has been increased from a bi-weekly, to a tri-weekly line.
1843. Penny Cycl., XXVI. 14/2. Semi- or tri-weekly newspapers.
1895. R. H. Sherard, in Bookman, Oct., 16/2. The tri-weekly supplement of La Lanterne.
1903. Daily Chron., 15 Jan. The tri-weekly expresses running across Siberia.
B. adv. a. Every three weeks. b. Three times a week.
1884. G. Pomeroy Keese, in Harper’s Mag., July, 300/1. A line of … coaches has been established, leaving tri-weekly.
1901. Daily News, 12 Jan., 5/3. In consequence of military restrictions … the advertisement sheet which has been appearing every week will be issued tri-weekly.
