Escalator was originally a combination of the word 'scala', which is Latin for steps, and the word 'elevator', which had already been invented. The verb form of the word is (to) escalate and is commonly applied to the use of increased force in warfare. The word Escalator started out as a trademark of the Otis Elevator Company. Otis, however, failed to police its usage sufficiently, so escalator became a generic term in 1950. But until then, other manufacturers had to market their escalators under different names. The Peelle Company called theirs a Motorstair, and Westinghouse called their model an Electric Stairway. The Haughton Elevator company (now part of Schindler Group) referred to their product as simply Moving Stairs.

An escalator is a conveyor transport device for transporting people, consisting of a staircase whose steps move up or down on tracks that keep the surfaces of the individual steps horizontal. A moving walkway, moving sidewalk, travelator, or travellator is a slow conveyor belt that transports people horizontally or on an incline in a similar manner to an escalator. In both cases, riders can walk or stand. The walkways are often supplied in pairs, one for each direction.

In 1892, Charles A. Wheeler patented ideas for the first practical moving staircase, though it was never built. Some of its features were incorporated in the prototype built by the Otis Elevator Company in 1899. Jesse W. Reno invented the first escalator and installed it as an amusement ride at Coney Island, New York in 1897. This particular device was little more than an inclined belt with wooden slats or cleats on the surface for traction. The incline was as steep as 25°. Reno sold this machine to the Otis Elevator Company in 1899, and together they produced the first commercial escalator which won a first prize at the Paris 1900 Exposition Universelle in France. Some escalators of this vintage were still being used in the Boston subway until 1994.

In Hong Kong, tens of thousands of commuters travel each work day between Central, the central business district, and the Mid-levels, a residential district hundreds of feet uphill, using a long distance system of escalators and moving sidewalks called the Central-Mid-Levels escalator. It is the world's longest outdoor escalator system (not a single escalator span), at a total length of 800 m. It goes only one way at a time; the direction reverses depending on rush hour traffic direction. The