A mitre (sometimes also spelled miter),or miter joint is a joint made by bevelling each of two parts to be joined, usually at a 45° angle, to form a corner, usually a 90° angle. It is often used in making picture frames. In woodwork, it is one way of joining two pieces of moulding that meet at an angle. (Compare to the cope cut.) In carpentry it is a joint to create a pleasing look to skirting boards (base trim) and architrave around door frames and windows or any feature requiring a moulding or a border. It is a popular method of joining as it is easy and attractive.

The Dimar Mitre Lock Bits are specifically designed to “lock” the two pieces of moulding. The result is a strong joint.