The word 'wristwatch' is a transparent Modern English compound, formed by directly combining two native English words. 'Wrist' originates from Old English, describing the flexible, twisting joint of the arm. 'Watch' evolved from the Old English concept of keeping awake during a period of vigil, which extended to mean a timepiece kept for guard duty and eventually any portable time-telling device. The compound logically emerged in the early 20th century to specifically designate a watch designed to be worn on the wrist, as opposed to a pocket watch, clearly describing its function and location of use. Its formation follows the common Germanic pattern of creating new terms by straightforwardly joining two existing nouns.

Structure: wrist (body part) + watch (timepiece) - wrist: From Old English wrist, related to wrīthan 'to twist'; denotes the joint connecting the hand to the arm. - watch: From Old English wæcce 'a watch, vigil', from wacian 'to be awake'; denotes an instrument for telling time.