(1) A machine or tool for cutting metal and other material by the closing motion of two sharp, closely adjoining edges; for example, squaring shear and circular shear. (2) An inclination between two cutting edges, such as between two straight knife blades or between the punch cutting edge and the die cutting edge, so that a reduced area will be cut each time. This lessens the necessary force, but increases the required length of the working stroke. This method is referred to as angular shear. (3) The act of cutting by shearing dies or blades, as in a squaring shear. (4) The type of force that causes or tends to cause two contiguous parts of the same body to slide relative to each other in a direction parallel to their plane of contact. (5) A tool for cutting metal and other material by the closing of two sharp, closely adjoining edges. (6) An, inclination between two cutting edges used to avoid cutting all at once. (7) The damage done to the cutting edges of trim steels by misalignment.
Source: The OHIO State University