VR stands for virtual reality and it is a simulated experience that can be similar to or completely different from the real world. 

The main piece of equipment is a VR headset that the person puts on and views the screen inside it. As the person moves their head, the VR headset detects this movement and changes what is displayed on the screen. This makes the person feel like they are there inside the virtual reality game or experience that is being displayed in the headset.

There are lots of different VR kits ranging from cardboard headsets that you put your phone into to VR headsets that come with controllers that enable you to interact with the game or experience.

There are also "room scale" VR headsets that get tracked by sensors which means that as you walk around the "real" room, your character in virtual reality will move around as well.