Thryfallow \Thry"fal`low\, v. t. [Perhaps fr. thrice + fallow. Cf. {Trifallow}.] To plow for the third time in summer; to trifallow. [R.] [Written also {thrifallow}.] --Tusser. [1913 Webster]
Thrifallow \Thri"fal`low\ (thr[imac]"f[a^]l`l[-o]), v. t. See {Thryfallow}, and {Trifallow}. [R.] --Tusser. [1913 Webster]