A labor union organized at the company level, often contrasted with industrial or craft unions. In Japanese context, it typically refers to an in-house union representing employees of a single company.
Japanese company unions are often organized on a per-company basis.
He was elected chairman of the company union.
労働組合 is a general term for labor union, while 会社組合 specifically refers to a union organized within a single company.
企業別組合 is a near-synonym emphasizing the enterprise-based structure, often used in academic or labor studies contexts.
Compound of 会社 (company) and 組合 (union, association).