The Collaborative International Dictionary of English v.0.48:

Stack \Stack\, v. t. [imp. & p. p. Stacked (st[a^]kt); p. pr.
   & vb. n. Stacking.] [Cf. Sw. stacka, Dan. stakke. See
   Stack, n.]
   1. To lay in a conical or other pile; to make into a large
      pile; as, to stack hay, cornstalks, or grain; to stack or
      place wood.
      [1913 Webster]

   2. Specifically: To place in a vertical arrangement so that
      each item in a pile is resting on top of another item in
      the pile, except for the bottom item; as, to stack the
      papers neatly on the desk; to stack the bricks.
      [PJC]

   3. To select or arrange dishonestly so as to achieve an
      unfair advantage; as, to stack a deck of cards; to stack a
      jury with persons prejudiced against the defendant.
      [PJC]

   To stack arms (Mil.), to set up a number of muskets or
      rifles together, with the bayonets crossing one another,
      and forming a sort of conical pile.
      [1913 Webster]