Adjustable wrench is a type of wrench with a movable jaw that adapts the tool to different sized objects.
Adjustable end wrench: the most common type of adjustable wrench in use today. The adjustable end wrench differs from the monkey wrench in that the gripping faces of the jaws are displaced to a (typically) 15 degree angle relative to the tool's handle, a design feature that facilitates the wrench's use in close quarters. The modern adjustable end wrench was first developed by Johansson or by the Crescent Tool and Horseshoe Company, and is often referred to as a "crescent wrench", regardless of the actual manufacturer.