The process of switching from the production of one product or part number to another in a machine (e.g., a stamping press or molding machine) or a series of linked machines (e.g., an assembly line or cell) by changing parts, dies, molds, fixtures, etc. (Also called a setup.) Changeover time is measured as the time elapsed between the last piece in the run just completed and the first good piece from the process after the changeover.

From the Lean Lexicon 5th Edition
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