A pallet was a wooden stand on which items were stacked for shipping.
In an alternate 1944, there was a stack of pallets in an alleyway where Alicia Travers, Carmine and his gangsters were having a shoot-out against some Nazis. There was another pallet sitting fairly close to that stack as well, that had a couple of cardboard boxes on top of it. (ENT: "Storm Front, Part II")
In 2022, a Toronto alley La'an Noonien-Singh and James T. Kirk were standing in was littered with broken pallets. (SNW: "Tomorrow and Tomorrow and Tomorrow")