noun | verb
pilepile1 /paɪl/ noun 
► pile a lot of things on top of each other: The books were arranged in neat piles on the table. There is a big pile of towels that need to be washed.
► heap a large messy pile of things: A heap of clothes lay on the floor.
► stack a group of things that have been neatly placed on top of each other: There was a stack of magazines on the table.
► mound a pile of something with a round shape: She had a huge mound of rice on her plate.
► mountain a very large pile of something. Mountain sounds informal: His desk is always covered in a mountain of papers.
noun | verb
pilepile2 /paɪl/ verb ► pile to put a lot of things on top of each other: Dirty dishes were left piled in the sink. Books were piled up on the desk.
► heap to put a lot of things on top of each other in a messy way: Jim heaped some more logs on the fire. Magazines were heaped on the table.
► stack to put things into a neat pile: We stacked the boxes neatly in one corner of the room.