Source: Link
Augmented Reality (AR) is a live, direct or indirect 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. As AR exists on top of our own world it provides as much freedom as you are given within your normal life. AR utilizes your existing reality and adds to it utilizing a device of some sort. Mobile and tablets are the most popular mediums of AR now, through the camera, the apps put an overlay of digital content into the environment. Custom headsets are also being used. As popular AR examples there are Pokemon Go and Snapchat’s new AR bitmojis.
Mixed Reality (MR), sometimes referred to as hybrid reality, is the merging of real and virtual worlds to produce new environments and visualizations where physical and digital objects co-exist and interact in real time. It means placing new imagery within a real space in such a way that the new imagery is able to interact, to an extent, with what is real in the physical world we know. The key characteristic of MR is that the synthetic content and the real-world content are able to react to each other in real time.
https://www.youtube.com/watch?v=Jd2GK0qDtRg&ab_channel=Microsoft
Virtual Reality is noted as being immersed digitally. Your senses are hijacked by the headset you are wearing. Sometimes other devices can be worn to be immersed as well like a vest or sensors on your legs (etc).
Extended Reality (XR) is a newly added term to the dictionary of the technical words. For now, only a few people are aware of XR. Extended Reality refers to all real-and-virtual combined environments and human-machine interactions generated by computer technology and wearables. Extended Reality includes all its descriptive forms like the Augmented Reality (AR), Virtual Reality (VR), Mixed Reality (MR). In other words, XR can be defined as an umbrella, which brings all three Reality (AR, VR, MR) together under one term, leading to less public confusion. Extended reality provides a wide variety and vast number of levels in the Virtuality of partially sensor inputs to Immersive Virtuality.