Second Life world is split on regions, which run on simulators, nicknamed in sim.
Each region is a 256m x 256m (65,536 m²) , and has no upper limit, even if building are not possible above 4096m.
Two types of regions are avaliable:
- full region, with 15000 prims and 100 avatars available.
- homestead regions, with 3750 prims and 20 avatars, and the computer ressources shared with 3 others.
- open space (since 2009) designed for light use and background, they are considered as unsuitable for roleplay usage due to their low limits (10 avatars, 750 prims) and the enforcement of the low usage.
The regions may be divided on parcels, owned by different people.
They may be regrouped in private estates, or leave in mainland and be managed by Linden Lab (the Second Life owners) directly.
Sim is commonly used for a region, even if it runs on a part of a simulator process (more info at http://wiki.secondlife.com/wiki/Sim).