Augmented reality is technology that enhances the real world through the use of sensory information (visual, audio, or otherwise) added to the actual view of the real world. For example, smartphones have applications that utilize augmented reality, such as Google Sky Map and GeoGoggle. Google Sky Map uses your smartphone to show names of stars and other celestial bodies in the patch of sky where the phone is pointing. AR is also used in many popular social media platforms, like Snapchat and Instagram, through face-tracking AR lenses.
AR is not the same as VR (virtual reality). In virtual reality, your entire field of view is replaced by a simulated environment. In augmented reality, the existing environment is still visible and enhanced with simulated objects or effects.