matchboard

English

edge of board with groove on left;
edge of board with matched tongue on right

matchboard flooring boards

Etymology

match +‎ board

Noun

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.