From WordNet (r) 3.0 (2006):
amass
v 1: collect or gather; "Journals are accumulating in my
office"; "The work keeps piling up" [syn: accumulate,
cumulate, conglomerate, pile up, gather, amass]
2: 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" [syn:
roll up, collect, accumulate, pile up, amass,
compile, hoard]