tare (n.1)
"kind of fodder plant, vetch," c.1300, perhaps cognate with or from Middle Dutch tarwe "wheat," from a Germanic source perhaps related to Breton draok, Welsh drewg "darnel," Sanskrit durva "a kind of millet grass," Greek darata, daratos "bread," Lithuanian dirva "a wheat-field." Used in 2nd Wyclif version (1388) of Matt. xxiii:25 to render Greek zizania as a weed among corn (earlier darnel and cockle had been used in this place); hence figurative use for "something noxious sown among something good" (1711).
tare (n.2)
"allowable difference between gross and net weight, deduction made from gross weight of goods to account for approximate weight of packaging or container holding them," late 15c., from Middle French tare "wastage in goods, deficiency, imperfection" (15c.), from Italian tara, Medieval Latin tara, from Arabic tarah, literally "thing deducted or rejected, that which is thrown away," from taraha "to reject."