A straitjacket is a garment shaped like a jacket with overlong sleeves. The ends of these can be tied to the back of the wearer, so that the arms are kept close to the chest with possibility of only little movement.

Although straitjacket is the most common form, strait-jacket is also frequently used, and in England, strait-waistcoat (archaic). The spellings straightjacket and straight-jacket are erroneous, when in fact, "strait" means "tight" or "narrow".

Straitjackets are used to restrain people who may otherwise cause harm to themselves and others. Its effectiveness as a restraint makes it of special interest in escapology. The straitjacket is also a staple prop in stage magic and is sometimes used in bondage games.

The negative connotations straitjackets have as an instrument of torture come from the earlier era of Victorian medicine. Physical restraint was then extensively used both as treatment for mental illness and as a means of pacifying patients in understaffed asylums.

Institutional straitjackets tend to be made of canvas or duck cloth for material strength. Jackets intended as fetish wear or fashion items often use leather or PVC instead.

Source: Wikipedia