tret

from The Collaborative International Dictionary of English v.0.48

Tret \Tret\, obs.
   3d pers. sing. pres. of {Tread}, for treadeth. --Chaucer.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Tret \Tret\, n. [F. traite a drawing, trading, journey, tax on
   wares in transit, anything diminishing the value of coins,
   fr. OF. traire to draw, L. trahere. See {Trait}.] (Com.)
   An allowance to purchasers, for waste or refuse matter, of
   four pounds on every 104 pounds of suttle weight, or weight
   after the tare deducted. --M'Culloch.
   [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

TRET, weights and measures. An allowance made for the water or dust that may 
be mixed with any commodity. It differs from tare. (q.v.)