To put together several things in one pile; to arrange in stacks.
collect or gather; "Journals are accumulating in my office"
get together
arrange into piles or stacks; "She piled up her books in my living room"
collect or gather; "Journals are accumulating in my office"; "The work keeps piling up"
get or gather together; "I am accumulating evidence for the man''s unfaithfulness to his wife"; "She is amassing a lot of data for her thesis"; "She rolled up a small fortune"