escalator

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A moving stairway consisting of steps attached to a continuously circulating belt.
2. n. An escalator clause.

Century Dictionary and Cyclopedia

1. n. A moving stairway. It is essentially a conveyer, employing two chains which form an endless belt that travels on a double track, passing over two large sheaves, one below the floor at the foot of the stairway and one under the floor at the head of the stairway. The links of the chains support the treads and risers of a flight of steps, each pair supporting one tread and one riser. When the tracks are level, as at the landings of the stairway, the treads and risers travel on two pairs of wheels, each pair moving on one track, and the treads form a continuous platform, the risers hanging below out of sight. Where the tracks are inclined they separate, one pair of wheels following the upper track and the other the lower track; the treads separate and the risers fill the spaces between the steps, thus forming a continuous traveling stairway. In operation the belt travels over the lower sheave up the stairway and, turning downward over the second sheave, returns with the treads and risers hanging below until they are again reversed in turning upward over the lower sheave. The two landings are thus traveling horizontal walks, and the stairway is a series of steps continually moving upward. The passenger steps upon the lower platform and stands still, the steps lifting him until the upper platform is reached, where he walks off upon the floor. At the side of the casing an endless hand-rail travels upward at the same speed as the stairway. Very large escalators have two stairways, one carrying passengers up and the other down. A single escalator, having steps three feet wide, has a capacity of six thousand passengers an hour. See conveyer.

Wiktionary

1. n. A motor-driven mechanical device consisting of a continuous loop of steps that automatically conveys people from one floor to another.
2. n. An upward or progressive course.
3. n. An escalator clause.

GNU Webster's 1913

1. n. 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; -- originally a trade term, which has become the generic name for such devices. Such devices are in common use in large retail establishments such as department stores, and in public buildings having a heavy traffic of persons between adjacent floors.

WordNet 3.0

1. n. a stairway whose steps move continuously on a circulating belt
2. n. 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)