A catwalk, in its most basic form, is any narrow platform on which people may walk. In this context, a catwalk may be found anywhere and can be anything. As a matter of fact, the name catwalk has been given to such things as suspended footbridges, mountain trails, and piers.
A catwalk can also mean pedestrian bridges perched atop busy streets (also called skyways), service and control platforms found in large theaters from which the lights and sounds can be controlled, and even the gun bridge on a whaling ship.
Recently, however, the word "catwalk" has taken on a much more specific image in our collective imaginations. As understood in the vernacular, it is generally meant as a long and narrow stage on which a person walks to display articles of clothing. This stage is usually elevated and may be flanked by seats on either side, usually reserved for an audience. The catwalk is kept narrow so that the clothes and accessories being exhibited can be observed more closely. A catwalk may also be called a runway, and is an indispensable part of any fashion show.
The term "catwalk" is believed to have originated from bridges that used to connect adjacent buildings, especially during construction or structural repair. These narrow walkways could rise quite high up above the ground and were designated the name "catwalk" not because of the presence of cats, but because of the cat's agility as well as its ability to land unharmed from relative heights. Because of the limited width and the height of these platforms, it was said that only a cat could walk the length of the platform with out trepidation.
The word "catwalk" entered the popular lexicon around the late 1800's. It made its first appearance in the Oxford English Dictionary in 1885.