a clause in a contract that provides for an increase or a decrease in wages or prices or benefits etc depending on certain conditions (as a change in the cost of living index)
A stairway or incline arranged like an endless belt so that the steps or treads ascend or descend continuously, and one stepping upon it is carried up or down; a trade term
An escalator is a moving staircase on which people can go from one level of a building to another. Moving staircase used as transportation between floors or levels in stores, airports, subways, and other mass pedestrian areas. The name was first applied to a moving stairway shown at the Paris Exposition of 1900. Modern escalators are electrically powered, driven by chain and sprocket, and held in place by two tracks. As the treads approach a landing, they pass through a comb device; a switch cuts off power if an object becomes jammed between comb and treads