|>>|| No. 18203
>Augmented reality (AR) is a live, copy, view of a physical, real-world environment whose elements are augmented (or supplemented) by computer-generated sensory input such as sound, video, graphics or GPS data.
In practice, this means you point your device's camera at the real world, and something is rendered on the screen as though it were really there, so when you move your camera, the rendered elements move with it. The idea has been around for a while but it's only become popular recently in areas like smartphone apps, Google likes it, the Nintendo 3DS uses it. Search YouTube for examples.
With regards to Ingress, which I don't believe uses a camera, it means the game-relevant stuff is drawn over your phone's map, so as you walk around in the real world, you have to use your phone to see where the invisible 'portal' things are located and capture them.