The Collaborative International Dictionary of English v.0.48:

Rummage \Rum"mage\ (?; 48), n. [For roomage, fr. room; hence
   originally, a making room, a packing away closely. See
   Room.]
   1. (Naut.) A place or room for the stowage of cargo in a
      ship; also, the act of stowing cargo; the pulling and
      moving about of packages incident to close stowage; --
      formerly written romage. [Obs.]
      [1913 Webster]

   2. A searching carefully by looking into every corner, and by
      turning things over.
      [1913 Webster]

            He has made such a general rummage and reform in the
            office of matrimony.                  --Walpole.
      [1913 Webster]

   Rummage sale, a clearance sale of unclaimed goods in a
      public store, or of odds and ends which have accumulated
      in a shop. --Simmonds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

rummage sale
    n 1: a sale of donated articles [syn: rummage sale, jumble
         sale]