The Collaborative International Dictionary of English v.0.48:

Accumulate \Ac*cu"mu*late\, v. t. [imp. & p. p. Accumulated;
   p. pr. & vb. n. Accumulating.] [L. accumulatus, p. p. of
   accumulare; ad + cumulare to heap. See Cumulate.]
   To heap up in a mass; to pile up; to collect or bring
   together; to amass; as, to accumulate a sum of money.
   [1913 Webster]

   Syn: To collect; pile up; store; amass; gather; aggregate;
        heap together; hoard.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Accumulate \Ac*cu"mu*late\ ([a^]k*k[=u]"m[-u]*l[=a]t), v. i.
   To grow or increase in quantity or number; to increase
   greatly.
   [1913 Webster]

         Ill fares the land, to hastening ills a prey,
         Where wealth accumulates, and men decay. --Goldsmith.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Accumulate \Ac*cu"mu*late\ (-l[asl]t), a. [L. accumulatus, p. p.
   of accumulare.]
   Collected; accumulated. --Bacon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

accumulate
    v 1: 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]
    2: collect or gather; "Journals are accumulating in my office";
       "The work keeps piling up" [syn: accumulate, cumulate,
       conglomerate, pile up, gather, amass]