The Collaborative International Dictionary of English v.0.48:

Pasteboard \Paste"board`\, n.
   1. A stiff thick kind of paper board, formed of several
      single sheets pasted one upon another, or of paper
      macerated and pressed into molds, etc.
      [1913 Webster]

   2. (Cookery) A board on which pastry dough is rolled; a
      molding board.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pasteboard
    n 1: stiff cardboard made by pasting together layers of paper