AR is where the user can see reality with a layer of digital content overlaid on it.
Often deployed by holding up a phone/iPad and seeing the camera view with a 3D digital scene matching and moving with the users camera, such that it looks like the digital content is in the real world.

I’ve made state of the art AR apps for GSK and F1 RedBull, as well as using the principles of augmented reality to use the Peppers Ghost effect for art works and festivals.