Tare and Tret, commercial terms, are deductions usually made from the gross weight of goods. Tare is the weight of the case or covering, box, or such-like, containing the goods; deducting this the net weight is left. Tret is a further allowance (not now so commonly deducted) made at the rate of 4 lb. for every 104 lb. for waste through dust, sand, etc.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Tarbes * Tarentum