Tool, usually operated by hand, for tightening bolts and nuts. A wrench basically consists of a lever with a notch at one or both ends for gripping the bolt or nut so that it can be twisted by a pull at right angles to the axes of the lever and the bolt or nut. Open-end wrenches have ends with straight-sided slots that fit over the part being tightened; box-end wrenches have ends that enclose the nut and have six, eight, 12, or 16 points inside the head. A socket wrench is essentially a short pipe with a square or hexagonal hole and either a permanent or a removable handle.

Variants of WRENCH

wrench or spanner

This entry comes from Encyclopædia Britannica Concise.
For the full entry on wrench, visit Britannica.com.

Seen & Heard

What made you look up wrench? Please tell us what you were reading, watching or discussing that led you here.