From Classic Encyclopedia 1911
STAPLE, a word which has had a curious and interesting development of meaning. The O. Eng. stapul meant a prop or support, and is to be referred to the root seen in step, stamp, &c.; the meaning is also seen in the cognate Du. stapel, stocks, pile, Ger. Staffel, step of a ladder, &c. The application, in current usage, of the word to a loop of wire or metal with two sharpened points used to fix a pin or bolt, or to fasten wire, &c., to wood, preserves the original sense. A special development in Low German of stapel gave the meaning of an orderly arranged heap of goods or stores, hence a store-house in which goods were arranged in a settled order, the idea of firmness or stability being that which runs through the changes of meaning to which the word has been subjected. This Low German word and sense was adapted in Old French as estaple, mod. Nape, and applied to an established market or town, particularly to one which was the centre of the trade in some specific commodity. Thence the word has in modern usage been transferred to a. principal or chief commodity or article of consumption.
In English economic history the term "staple" was applied to those towns which were appointed by the king as the centres for the trade of the company of the merchants of the staple. These merchants had a monopoly in the purchase and export of the staple commodities of England, viz. wool, woolfels, leather, tin and lead. The merchants of the staple were the origin of all English trading companies. The trade of the staple towns was under the management of a mayor and constables, sometimes appointed by the merchants themselves, sometimes by the mayor of the town and sometimes by the king himself. W. Stubbs (Const. Hist. vol. ii.) dates the growth of the system from the reign of Edward I. The monopolies of the staple were from time to time abolished and restored, but they were consolidated by a statute of 1353, the number and place of the staples being fixed, the custom declared, and the rights and privileges of the merchants confirmed. (See C. Gross, Gild Merchants; W. Cunningham, Growth of English Industry and Commerce.)