an area in virtual reality perceived by users to be a place you can move around in
made popular originally by games like Doom and Unreal, and books by writers like William Gibson (Neuromancer) and Neal Stephenson (SnowCrash)
if the virtual space is large enough, whole houses, cities, continents, planets can be defined and built, and usually a user can travel around and interact with all parts of that virtual space
In SnowCrash, Hiro built his house on the main drag of the Metaverse - a personal virtual space within a shared virtual space. When you entered his virtual house, it expanded inside to a virtual space many times larger than the outside would suggest. You can do that with virtual spaces.
"Hey dude! Get your virtual ass out of my virtual space! Or I'll frag your sorry ass!"