# Shear

• In physics and mechanics, shear refers to deformation in which parallel surfaces slide past one another (as opposed to compression and tension, in which parallel surfaces move towards or away from one another).
• Shear is also a form of structural failure. A component fails by shearing when it splits into two parts that slide past each other. See shear stress and shear strength.
• In the skin shear is the movement of the epidermis over the underlying dermis producing friction, tearing and splitting of the layers. In some cases it can produce hyperkeratosis or rapid skin growth in the area of shear.
• In mathematics, a shear is a particular kind of linear mapping. Mathematical shears are also called transvections.
• In clothing design, fabric may be cut on the shear (also referred to as the bias). This is done by placing the patterns at 45° to the weave of the fabric. Clothing cut on the shear is less stiff and follows the shape of the wearer's body more closely than clothing cut parallel to the weave.
• Wind shear is a difference in wind speed or direction between two wind currents in the atmosphere.
• In lockpicking a cylinder lock, the shear line is where the inner cylinder ends and the outer cylinder begins.
• Sheep-shearing is the process of removing the wool from a sheep.
• In metalworking, a shear is a machine used to cut sheet metal. See guillotine.
de:Scherung

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