matchboards

Noun

matchboard (countable and uncountable, plural matchboards)

1. 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.