The Collaborative International Dictionary of English v.0.48:

Dosser \Dos"ser\, n. [LL. dosserum, or F.dossier bundle of
   papers, part of a basket resting on the back, fr. L. dorsum
   back. See Dorsal, and cf. Dosel.] [Written also dorser
   and dorsel.]
   1. A pannier, or basket.
      [1913 Webster]

            To hire a ripper's mare, and buy new dossers.
                                                  --Beau. & Fl.
      [1913 Webster]

   2. A hanging tapestry; a dorsal.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dosser
    n 1: someone who sleeps in any convenient place [syn: dosser,
         street person]