English edit

 
edge of board with groove on left;
edge of board with matched tongue on right
 
matchboard flooring boards

Etymology edit

match +‎ board

Noun edit

matchboard (countable and uncountable, plural matchboards)

  1. (carpentry) A type of wooden board that connects with others using a tongue and groove system
  2. (sand casting) A thin piece of material (such as wood, plaster, or metal) that forms and aligns the matched parting surfaces for the two parts (the cope and the drag) of a molding box or flask, to which board patterns are attached in some casting methods.
 
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Derived terms edit