The Collaborative International Dictionary of English v.0.48:

Tarpaulin \Tar*pau"lin\, n. [Tar + palling a covering, pall to
   cover. See Pall a covering.]
   1. A piece of canvas covered with tar or a waterproof
      composition, used for covering the hatches of a ship,
      hammocks, boats, etc.
      [1913 Webster]

   2. A hat made of, or covered with, painted or tarred cloth,
      worn by sailors and others.
      [1913 Webster]

   3. Hence, a sailor; a seaman; a tar.
      [1913 Webster]

            To a landsman, these tarpaulins, as they were
            called, seemed a strange and half-savage race.
                                                  --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tarpaulin
    n 1: waterproofed canvas [syn: tarpaulin, tarp]