Thwaite definitions Webster's 1828 Dictionary THWAITE, n. A fish, a variety of the shad. 1. A ... rel. to OE thwitan to cut Webster's 1913 Dictionary Thwaite Thwaite, n. (Zo["o]l.) The twaite. Webster's 1913 Dictionary Thwaite Thwaite, n. [CF. Icel. [thorn]veit a piece of land, ...