A try square or try-square is a woodworking tool used for marking and checking 90° angles on pieces of wood. Though woodworkers use many different types of square, the try square is considered one of the essential tools for woodworking.[1]
The square in the name refers to the 90° angle. To try a piece of wood is to check if the edges and faces are straight, flat, and square to one another.[2] A try square is so called because it is used to try how square the workpiece is.[3]