A zipper is a slide fastener with two edges of teeth attached to a fabric tape. The teeth lock into a snug fit when they are drawn together by a slide. When the slide is pulled back, the teeth separate.

The zipper was invented by Whitcomb L. Judson, a Chicago, Illinois, mechanical engineer, to relieve the tedium of fastening by hand the fashionable high-buttoned boots of the time. Judson's fastener, called the Clasp Locker and patented in 1893, consisted of a movable guide that meshed together two sets of hooks and eyes. Judson also invented a machine to mass produce his fasteners cheaply. However, the machine broke down frequently and the fastener itself had a way of spontaneously unfastening.

In 1905 Judson invented an improved fastener, the C-curity, but like its predecessor, it tended to break open unexpectedly. Perhaps for this reason, clothing manufacturers showed no interest in the device. It was Gideon Sundback (1880-1956), a Swedish engineer employed by Judson, who developed the first really practical and successful slide fastener. Sundback's 1913 invention used small, interlocking teeth that were flexible and remained locked together. (Catharina Kuhn-Moos patented a similar fastener in Europe the same year.) Sundback also invented efficient machinery to produce his improved fastener cheaply.

Although the slide fastener was now ready to be mass-produced for wide spread usage, clothing manufacturers continued to ignore it--except for one, which contracted in 1918 to supply the United States Navy with flying suits equipped with the device. Judson's company suddenly had an order for thousands of the fasteners.

Manufacturers began to realize how useful the fastener could be. Soon it appeared in gloves and tobacco pouches. In 1923 the B.F. Goodrich Company added the slide fasteners to their rubber galoshes, calling this new footwear design "Zippers," which from then on became the popular name for the fastener itself. Zippers finally appeared on clothing, first in men's pants, and, in the late 1920s, in women's garments. Today's design is little changed from Sundback's original.