#29 Discount, tare, tret & cloff...History and Etymology of Math Terms

Discount

In the great markets of Italy, the competition could be harsh, and so the enterprising businessman would offer a little incentive to the reluctant buyer. If a Merchant buying spices for shipment surveyed the counting board and seemed hesitant, the seller would sweep a few stones to the side, away from the count. These would be included free if the buyer bought the ones counted. The Latin roots of discount reflect the early counting table origins, the dis indicating a reversal or movement away from, and the count from computare. When the French picked up the practice they called it d'escompte. By the middle of the 17th century, the English had begun to apply the practice in the pepper trade with Holland using the current word discount.

Three special types of discounts took on their own names, and problems regarding them were common in arithmetic books in the 18th and 19th centuries. Tare represented a discount, or adjustment against the weight of the container. The Latin root tara for waste. The same word is used for several types of weeds that grow among grain crops but are worthless and thus "thrown away" at harvest. Tret is so old that even the OED states, "The reason or ground of the allowance was apparently forgotten already in the 17th c., and has been variously given since." Tret was a discount or reduction of the weight to allow for possible loss in shipping, or unusable product such as dust, defective or poor quality product, etc. It seems to have been established in England as about 1/26 of the net weight after the gross had been reduced by tare. Cloff is also of obscure origin. The OED defines cloff as "An allowance (now of 2 lbs. in 3 cwt., or 1/168), given with certain commodities, in order that the weight may hold good when they are sold by retail." All three terms appear in many popular arithmetics in England and the US. Here is a copy of a page addressing all three topics from Hill's Arithmetic from 1772 at the Pitt Digital Library.  This link no longer seems to work, but if you find another on this, please share.