What is meant by pallet racking?

Pallet racking refers specifically to a storage system designed to hold materials on pallets, which are flat transport structures used to support goods in a stable manner. This method efficiently organizes warehouses and distribution centers by utilizing vertical space, allowing for better inventory management and retrieval processes. Using pallets enables the easy movement of bulk goods and products, facilitating faster access and increased storage density.

The other choices do not accurately describe pallet racking: storing materials in bins relates to a different storage method that does not utilize pallets; transporting items vertically encompasses methods such as lifts or conveyors, which are not specific to the concept of pallet racking; and sorting items into categories involves organizing items but does not directly pertain to the structural aspect of pallet racking. Thus, the emphasis on storing materials on pallets in racks is what defines pallet racking and makes it the correct answer.