IPA: /ˈrɪstˌwɒtʃ/
KK: /ˈrɪstˌwɑtʃ/
A small timepiece that is worn on the wrist, usually secured with a strap or bracelet.
She checked her wristwatch to see the time before the meeting.
Wristwatch → It is formed from "wrist" (from Old English "wrist", meaning the joint connecting the hand and forearm) and "watch" (from Old English "wæccan", meaning to be awake or to watch). A wristwatch is a device worn on the wrist to keep track of time, hence it is a watch that you wear on your wrist.
Think of the 'wrist' as the place where you wear the 'watch' — a wristwatch is simply a watch that you wear on your wrist.
No commonly confused words.