What is a Android Wear?

The Android Watch is Wearable.
Android Wear is an operating system that is prevalent on the nascent smartwatch and wearable space. Though typically tethered to a mobile device, the OS has some of the same functionality as what you would find on a smartphone, and has Google Now functionality built in. A number of manufacturers have either one out to market or have one coming: Motorola, LG, Samsung, HTC, ASUS among others.