The Collaborative International Dictionary of English v.0.48:

Assemble \As*sem"ble\, v. t. [imp. & p. p. Assembled; p. pr. &
   vb. n. Assembling.] [F. assembler, fr. LL. assimulare to
   bring together to collect; L. ad + simul together; akin to
   similis like, Gr. ? at the same time, and E. same. Cf.
   Assimilate, Same.]
   1. To collect into one place or body; to bring or call
      together; to convene; to congregate.
      [1913 Webster]

            Thither he assembled all his train.   --Milton.
      [1913 Webster]

            All the men of Israel assembled themselves. --1
                                                  Kings viii. 2.
      [1913 Webster]

   2. To collect and put together the parts of; as, to assemble
      a bicycle, watch, gun, or other manufactured article.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

assembling
    n 1: the act of gathering something together [syn: collection,
         collecting, assembling, aggregation]