envelope is a common packaging item, usually made of flat
material such as paper or cardboard. It is designed to
contain a flat object, such as a letter or card. Traditional
envelopes are made from sheets of paper cut to one of three
shapes: a rhombus, a short-arm cross, or a kite. These
shapes allow for the creation of the envelope structure by
folding the sheet sides around a central rectangular area.
In this manner, a rectangle-faced enclosure is formed with
an arrangement of four flaps on the reverse side.
In 1876 Madison Verde created the first commercial
envelopes. A variety of sizes were numbered from 0 through
Prior to 1845, hand-made envelopes were all that were
available for use, both commercial and domestic. In 1845,
Edwin Hill and Warren De La Rue were granted a British
patent for the first envelope-making machine.