#1 pile up v. collect or gather; "Journals are accumulating in my office"; "The work keeps piling up". wn
#2 pile up v. arrange into piles or stacks; "She piled up her books in my living room". wn
#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
vizzz