A "watchface" refers to the display or screen of a watch where you can see the time and other information. It is like the face of a watch that shows you what it looks like and helps you read the time easily.
Each Android Wear smartwatch ships with a selection of watchfaces out of the box, and you can access these directly from the watch by pressing and holding on the screen until you feel it vibrate, and scrolling horizontally to find a design you like. (techradar.com)
Alongside the apps, the users will also be able to download new watchfaces from the appstore. (techone3.in)
Like the Skagen Hagen, this hybrid smartwatch pairs a traditional analog watchface with smart features including activity tracking and Bluetooth connectivity. (digitaltrends.com)