A stacker is a noun that refers to a mechanical machine or a person who arranges objects neatly on top of each other in a pile or stack. Full definition
The Logan Diaper Stacker keeps diapers within reach while adding to the beauty of the nursery. (simplybabyfurniture.com)
This sequel continues after the first one, following John Boyega as Jake Pentecost, the son of Idris Elba's character Stacker Pentecost from the original movie. (firstshowing.net)
Baby ring stacker with 5 wooden colored rings that can be stacked on the base's peg. (gatortots.com)