宇

Concrete: The eaves or overhang of a roof; specifically, the boundary where interior shelter meets the exterior.

Abstract: The "canopy" of the world; the spatial dimension of the universe. In the compound 宇宙, 宇 typically represents space (extent), while 宙 represents time (ages).

Functions primarily as a noun or as an attribute describing things pertaining to the house or the universe.

[DISTINITIONS]

Distinguish from 屋 (//wū//, room/dwelling) and 家 (//jiā//, household/family unit); 宇 focuses on the physical envelope or span of the structure.

When encountering ambiguity, determine if the author is emphasizing shelter (the concrete eaves/overhang) or extent (the abstract spatial canopy).