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]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "amassed":
   accumulated, agglomerate, aggregate, assembled, backlogged,
   bunched, bundled, clumped, clustered, collected, combined,
   conglomerate, congregate, congregated, cumulate, fascicled,
   fasciculated, garnered, gathered, glomerate, heaped, hoarded,
   in session, joined, joint, knotted, laid up, leagued, lumped,
   massed, meeting, packaged, piled, stacked, stockpiled, stored,
   treasured, wrapped up