The Collaborative International Dictionary of English v.0.48:

matchboard \matchboard\ n.
   A board that has a groove cut into one edge and a tongue cut
   into the other so they fit tightly together (as in a floor);
   see match boarding.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

matchboard
    n 1: a board that has a groove cut into one edge and a tongue
         cut into the other so they fit tightly together (as in a
         floor)