A cloak is a type of loose garment that is worn over indoor clothing and serves the same purpose as an overcoat—it protects the wearer from the cold, rain or wind for example, or it may form part of a fashionable outfit or uniform. Cloaks are as old as human history; there has nearly always been some form of long outer garment used to protect people from the weather. Over time cloaks have changed their look to match current styles and textile needs.
Cloaks generally fasten at the neck or over the shoulder, vary in length, from ankle all the way up to the hip, mid-calf being the normal length. They may have an attached hood, and may cover and fasten down the front, in which case they have holes or slits for the hands to pass through. However, cloaks are almost always sleeveless.
Ladies may wear a long (over the shoulders or to ankles) cloak usually called a cape, or a full-length cloak. Gentlemen wear an ankle- or full-length cloak. Formal cloaks often have expensive, coloured linings and trimmings such as silk, satin, velvet and fur.
Figuratively, a cloak may be anything that disguises or conceals something. In many science fiction worlds such as Starcraft and Star Trek, there are cloaking devices, which provide a way to avoid detection.
Because they keep a person hidden, the phrase cloak and dagger has come to refer to espionage and secretive crimes: it suggests murder from hidden sources. "Cloak and dagger" stories are thus mystery, detective, and crime stories of this atmosphere.
In the Star Wars universe several Jedi wear cloaks usually in varying shades of brown, blue, or sometimes black, while the Sith prefer black.
Many superheroes, such as Batman and Superman, wear cloaks or capes as part of their costume.