Wedge (mechanical device)

A wedge is a portable double inclined plane, used either to separate two objects, or portions of objects, or hold an object in place, through the application of force, perpendicular to the inclined surfaces, developed by conversion of force applied to the wide end. The mechanical advantage of a wedge depends on the ratio of its length to its thickness. Where a short wedge with a wide angle does the job faster, it requires more force than a long wedge with a smaller angle.
See more at Wikipedia.org...