A Waco is the cardboard bin in the backroom that’s used in the aisles, on the shelves to organize backstocked product. It gets its name from the city where they’re made, Waco.
POG is short for Plan-O-Gram. They tie an item to a specific aisle, shelf, and space on the shelf. That way when you scan a product you can find where it is in the store. This includes all products in the store except the hanging items in Style and any item that is flexed out. Flex items should be store tied though so other TMs can find the items. This is a very watered down explanation of what a POG is, if you want more details there are plenty of former presentation and signing TMs who could share years worth of knowledge with you 🙂