The slowest operation (choke point) in a manufacturing process.

Do not confuse this with a company’s “Constraint” taken from TOC (Theory of Constraints), which is the slowest operation in an entire manufacturing system that, if remedied, would increase overall company throughput.

Example: In a work cell containing 5 dissimilar machines, the 3rd machine in the cell takes twice as long to cycle as the other machines. No products will leave this cell until they have gone through the slowest process or “bottleneck” (machine #3). This is the “bottleneck” operation in this cell.