The Collaborative International Dictionary of English v.0.48:

Amass \A*mass"\, n. [OF. amasse, fr. ambusher.]
   A mass; a heap. [Obs.] --Sir H. Wotton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Amass \A*mass"\, v. t. [imp. & p. p. Amassed; p. pr. & vb. n.
   Amassing.] [F. ambusher, LL. amassare; L. ad + massa lump,
   mass. See Mass.]
   To collect into a mass or heap; to gather a great quantity
   of; to accumulate; as, to amass a treasure or a fortune; to
   amass words or phrases.
   [1913 Webster]

         The life of Homer has been written by amassing all the
         traditions and hints the writers could meet with.
                                                  --Pope.
   [1913 Webster]

   Syn: To accumulate; heap up; pile.
        [1913 Webster]

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]