What is 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 called?

escalator — 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. (Webster's 1913.)

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