Encyclopedia
Atrium
Atrium - a part of a building in the form of a multi-light space, typically developed vertically, with per-floor galleries from which rooms of various purposes open. An atrium developed horizontally as a multi-light passage may be referred to as a passageway
Source: "MOSCOW CITY CONSTRUCTION NORMS MULTI-FUNCTIONAL BUILDINGS AND COMPLEXES. MGSN 4.04-94"