A picture is worth a thousand words so:
Here is a picture of pallets that fit nicely together when not in use. Similar to Styrofoam coffee cups, these pallets save space when not loaded with product (or coffee!)
Most often plastic pallets from one manufacturer will not “nest” with pallets from another manufacturer. There are occasions when manufacturers work together to provide pallets that meet an industry standard, such as the Grocery Manufacturers Association (GMA). These pallets will all nest together.