A spanner or wrench is a tool used to provide grip and mechanical advantage in applying torque to turn objects—usually rotary fasteners, such as nuts and bolts—or keep them from turning.
In British English, spanner is the standard term. The most common shapes are called open-ended spanner and ring spanner. The term wrench refers to a type of adjustable spanner.
In American English, wrench is the standard term. The very most common shapes are called open-end wrench and box-end wrench. In American English, spanner refers to a specialized wrench with a series of pins or tabs around the circumference. (These pins or tabs fit into the holes or notches cut into the object to be turned.) In American commerce, such a wrench may be called a spanner wrench to distinguish it from the British sense of spanner.