From 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]
From 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)