The term 'corner joints' refers to the type of joint used to join two pieces of wood at a corner. The most common type of corner joint is the miter, which is a 6-letter word that can be found in a crossword puzzle. A miter joint is created by cutting two pieces of wood at an angle and then joining them together to form a 90-degree angle. This type of joint is often used in carpentry and woodworking projects, such as picture frames, crown molding, and baseboards.