From SCP: Secret Laboratory English Official Wiki

Locations
Site-02, also known as the "Master Site" is one of the many Sites owned by The Foundation. Site-02 has two experimental technologies in it, the Micro H.I.D. and C.A.S.S.I.E.
Site-02 is made up of 4 zones, with most SCPs being stored in the Heavy Containment Zone.
Weapons, Lockers and Medkit Cabinets are found through out the Light and Heavy Containment Zones.

Zones
The main 4 sections of Site-02

Structures
Things that spawn within the zones. Most of these will randomly spawn.

Conceptual locations
These locations are concepts represented in gameplay, but do not correspond to a physical location as of yet.