In 1876 William Irwin Martin go published the Stationer's Handbook. He worked for the Samuel Raynor & Company in New York. He created the first commercial sizes of envelopes and simply numbered them from 0 through 12.

An envelope is a packaging product, usually made of flat material such as paper or cardboard, and designed to contain a flat object, which in a postal-service context is usually a letter, card or bills. 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 in the course of envelope manufacture 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 symmetrical.