"kind of fodder plant, vetch," early 14c., perhaps cognate with M.Du. tarwe "wheat," from P.Gmc. *tarwo, cognate with Bret. draok, Welsh drewg "darnel," Skt. durva "a kind of millet grass," Gk. darata, daratos "bread," Lith. dirva "a wheat-field." Used in 2nd Wycliffe version (1388) of Matt. xxiii:25 to render Gk. zizania as a weed among corn (earlier darnel and cockle had been used in this place); hence fig. use for "something noxious sown among something good" (1711).
"difference between gross and net weight," 1486, from M.Fr. tare "wastage in goods, deficiency, imperfection" (15c.), from It. tara, from Arabic tarah, lit. "thing deducted or rejected," from taraha "to reject."