envelope

An envelope is a packaging product, usually made of flat, planar material such as paper or cardboard, and designed to contain a flat object, which in a postal-service context is usually a letter or card. The traditional type is made from a sheet of paper cut to one of three shapes: the rhombus (also referred to as a lozenge or diamond), the short-arm cross, and the kite. These designs ensure that when the sides of the sheet are folded about a delineated central rectangular area, a rectangular-faced, usually oblong, enclosure is formed with an arrangement of four flaps on the reverse side, which, by virtue of the shapes of sheet traditionally used, is inevitably International trade in envelopes is relatively small, since envelopes tend to be manufactured close to where they are ultimately used. Nonetheless, U.S. converters have expanded their exports, mostly to nearby trading partners such as Canada and Mexico. The North American Free Trade Agreement (NAFTA) with Mexico and Canada, ratified by the United States in 1993, was expected to help expand the exports of efficient U.S. converters.