A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding the edges of an opening of fabric or other flexible material, such as on a garment or a bag. The physical parts of the zipper are: scoop teeth, chain, lock, pull tape, and slider. Zippers used in industrial clothing are metal or brass. Plastic zippers are used in typical apparel garments. Zippers are used as a closure in pants, skirts, and dresses.
- increase or decrease the size of an opening to allow or restrict the passage of objects, as in the fly of trousers or in a pocket;
- join or separate two ends or sides of a single garment, as in the front of a jacket, or on the front, back, or side of a dress or skirt to facilitate dressing;
- attach or detach a separable part of the garment to or from another, as in the conversion between trousers and shorts or the connection or disconnection of a hood and a coat;
- attach or detach a small pouch or bag to or from a larger one. One example of this is military rucksacks which have smaller pouches or bags attached on the sides using one or two zippers;
- be used to decorate an item.