This article is about the fastening device called the zip. For information on the acronym ZIP, please see that article.
A zipper (zip fastener or zip in British English) is a device for temporarily joining two edges of fabric together. It is widely used in clothing and other textiles.
The bulk of a zip consists of two strips of fabric tape, one permanently fixed to each of the two flaps to be joined, and each carrying tens or hundreds of specially shaped metal or plastic teeth. Another part, the slider, which is operated by hand, rides up and down the two sets of teeth. Inside the slider is a Y-shaped channel that pushes the opposing sets of teeth together or apart, depending on the slider's direction of travel. The zip is usually fitted vertically in clothing so that pushing the slider from top to bottom opens it, and pushing it from bottom to top closes it. If the slider got lose then the zipper becomes non-functinal and needs to fix it .The friction of the slider against the teeth causes a characteristic buzzing noise which is probably the origin of the name zip.
An early device similar to the zip, 'an Automatic, Continuous Clothing Closure', was patented in the USA by Elias Howe in 1851, but did not reach the market. Whitcomb Judson patented a similar 'Clasp Locker', for fastening shoes, in 1891 or 1893, and marketed the invention through his 'Universal Fastener' company. These two designs used hooks and eyes. The design used today, based on interlocking teeth, was invented by an employee of Judson's, Swedish scientist Gideon Sundback, in 1913 as the 'Hookless Fastener' and patented in 1917 as the 'Separable Fastener'. The B. F. Goodrich Company coined the name 'Zipper' in 1923, and used the device on tobacco pouches and boots. The zip became popular for children's clothing and men's trousers in the 1920s and 1930s. At this stage, the zip was permanently joined at one end, so could not be used to fasten jackets.