stacker

noun6

1. •
   Any person or thing that stacks.

   • As behavioral scientists we are not good block stackers — we don't replicate enough or build systematically across knowledge bases. — 1991
2. •
   A worker who stacks the shelves in a supermarket.
3. •
   A participant in sport stacking.
4. •
   Any device allowing items to be stacked.

   • a spring-loaded plate stacker in a cafeteria
5. •
   An output bin in a document feeding or punch card machine (contrast with hopper).
6. •
   (informal) A person who collects precious metal in the form of various small objects such as coins and bars.