A stack of stuff is a term used to describe a large collection of items that are piled up in an organized manner. It is often used to refer to a large number of items that need to be sorted or stored, such as books, papers, or other objects. The term 'stack of stuff' can also be used to describe a large group of people or animals that are gathered together in one place. The crossword solution for the term 'stack of stuff' is 'PILE, ' which is a four-letter word.