tare

tare (http://definr.com/tare)

     n 1: any of several weedy vetches grown for forage
     2: weedy annual grass often occurs in grainfields and other
        cultivated land; seeds sometimes considered poisonous
        [syn: darnel, bearded darnel, cheat, {Lolium
        temulentum}]
     3: counterweight consisting of an empty container that is used
        as a counterbalance to obtain net weight