noun
company office building; company premises
Refers to a building owned or used by a company, especially an office building; often used in business, news, and real-estate contexts.
新しい社屋が来月完成する。
The new company office building will be completed next month.
駅前に本社の社屋がある。
The headquarters building is in front of the station.
会社 means a company or workplace in general; 社屋 refers only to the physical building used by a company.
A Sino-Japanese compound written with 社, associated here with a company, and 屋, meaning building or house. The spelling directly reflects the idea of a company building.