definition of
[pile up]

[1] #1 pile up v. collect or gather; "Journals are accumulating in my office"; "The work keeps piling up". wn

[2] #2 pile up v. arrange into piles or stacks; "She piled up her books in my living room". wn

[3] #3 pile up v. 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". wn