A moving staircase that automatically carries people up or down between different levels.
From 'escalade' (climbing) mixed with '-ator' (device that performs an action). The device was patented in the early 1900s and named to suggest motion and climbing.
Escalator was invented in the 1890s, and the word is actually a trademark that became so popular it turned into a common word—like Xerox or Band-Aid! The word itself describes exactly what it does: escalate you upward.
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