What is the difference between dadoes and grooves?

• A. Dadoes are shorter than grooves
• B. Dadoes are decorative; grooves are functional
• C. Dadoes are cut across the grain while grooves are cut with the grain
• D. Dadoes are disallowed in modern carpentry

Answer: (C)

In woodworking, the way the cut relates to the grain defines what you’re making. A dado is a slot cut across the grain into a workpiece to receive another piece at a right angle—think a shelf sliding into the sides of a cabinet. A groove, on the other hand, runs along the length of the board with the grain and is used to guide or hold something along that direction. So the difference is orientation: dadoes are cross-grain cuts, grooves are along-grain cuts. The other statements don’t hold up: a dado isn’t inherently shorter than a groove, grooves aren’t strictly decorative, and both joinery methods are common in modern carpentry.