1A corner or nook — the recessed space at the edge of a room or object.
猫が部屋の隅で丸くなって眠っていた。
A cat was curled up sleeping in the corner of the room.
荷物を部屋の隅に置いておいた。
I left the luggage in the corner of the room.
本棚の隅に埃がたまっていた。
Dust had accumulated in the corner of the bookshelf.
彼は教室の隅の席に座るのが好きだ。
He likes to sit in the corner seat of the classroom.
2In Noh theater terminology, the stage position near the metsuke-bashira pillar (roughly, downstage right); an old, specialized usage.
能の舞台では、脇役が隅（すみ）に配置されることが多い。
On a Noh stage, supporting actors are often positioned at the 'sumi' (downstage right).