A chiton (Greek: χιτών, khitōn) was a form of clothing and is a sewn garment, unlike the peplos, a draped garment held on the shoulders by a fibula.

There are two forms of chiton, the Doric chiton and the later Ionic chiton. The "Doric" style was simpler and had no "sleeves", being simply pinned, sewn, or buttoned at the shoulder. The "Ionic" style was made of a much wider piece of fabric, and was pinned, sewn, or buttoned all the way from the neck to the wrists and the excess fabric gathered by the zone or girdled at the waist. By the late Archaic, Ionic chitons had become less common, especially for men.

The Doric chiton is a single rectangle of woolen or linen fabric. It can be worn plain or with an overfold called an apotygma which is more common to women. It can be draped and fastened at the shoulder by pins (fibulae) or sewing, or by buttons. The Ionic chiton could also be made from linen or wool and was draped without the fold and held in place from neck to wrist by several small pins. A large belt called a zoster could be worn over the chiton, usually under the breast ("high-girdled") or around the waist ("g low-girdled") or a narrower "zone" or girdle could be used. The chiton's length was greater than the height of the wearer, so excessive fabric was pulled above the belt, like a blouse.

The term costume can refer to wardrobe and dress in general, or to the distinctive style of dress of a particular people, class, or period. Costume may also refer to the artistic arrangement of accessories in a picture, statue, poem, or play, appropriate to the time, place, or other circumstances represented or described, or to a particular style of clothing worn to portray the wearer as a character or type of character other than their regular persona at a social event such as a masquerade, a fancy dress party or in an artistic theatrical performance.

One of the more prominent places people see costumes is in theatre, film and on television. In combination with other aspects, theatrical costumes can help actors portray characters' age, gender role, profession, social class, personality, ethnicity, and even information about the historical period/era, geographic location and time of day, as well as the season or weather of the theatrical performance. Often, stylized theatrical costumes can exaggerate some aspect of a character; for example Harlequin and Pantaloon in the Commedia dell'arte.