noun (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)(noun.communication)

  Synonym:
  escalator clause
  

  source: wordnet30
• a stairway whose steps move continuously on a circulating belt(noun.artifact)

  Synonym:
  moving staircase, moving stairway
  

  source: wordnet30
• 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.(noun)

  source: webster1913