Apple.com: Apple Watch Features
Now your inner circle is always nearby. Press the button next to the Digital Crown to access Friends, a place where you’ll see thumbnails of those you like to stay in touch with most. Tap one to send a message, make a call, or reach out in one of the new ways only Apple Watch makes possible.
The description reads, “Press the button next to the Digital Crown.” Apple must have a name for this button that is better than just a description of the button’s location. I wonder if the name of the button gives away something about the functionality of the watch that Apple is still keeping secret.