Wearable tech is, quite simply, technology you wear, such as a smartwatch or fitness tracker.
Technology has, over the years, decreased in size as it is improved and refined. Now that it is so small and convenient, the logical step is to make it into tech that can be worn, rather than held.
One of the biggest breakthroughs in this area (although only available for a while as an experiment), was Google Glass. A pair of glasses containing a battery, a camera, a screen, and a microphone which could keep you constantly connected while on the go.
From Google Glass to fitness trackers which you can attach to your laces, wearable tech is now limited only by imagination.