Pallet rack is a material handling storage aid system designed to store materials on pallets (or “skids”). Although there are many varieties of pallet racking, all types allow for the storage of palletized materials in horizontal rows with multiple levels. Forklift trucks are usually an integral part of any pallet rack system as they are usually required to place the loaded pallets onto the racks for storage. Since the Second World War, pallet racks have become an essential and ubiquitous element of most modern warehouses, manufacturing facilities, retail centers, and other storage and distribution facilities.
Definition from ‘https://en.wikipedia.org/wiki/Pallet_racking’