Worn device
A worn device is one that is ubiquitous and on the body all the time. Examples include:
- wristwatch
- ring
- wallet
- pager
- walkman
- cell phone
- cordless phone (in some environments supporting PCS protocol, the headset or handset is worn on the head or belt)
The term mobile device is often used to mean higher-tech worn devices, but there is no real difference in form factor, except that a mobile device is probably more likely to have a display screen, whereas most of the above don't.