The term tongue and groove refers to an assembly technique that joins two like materials together, edge to edge, to create a single flat surface. It is commonly used for many types of wood and laminate flooring. Each floorboard piece has a protruding tongue on one side and a receiving groove on the other. The tongue side fits into the adjoining piece’s groove side firmly, creating a tight, solid seam, eliminating the need for nails and screws. Certain organization such as the National Wood Flooring Association (NWFA) have released guidelines that govern exact proportions for each of these elements.