Final answer:
A labor union is an organization of workers that negotiates with employers over wages and working conditions, and this process is called collective bargaining.
Step-by-step explanation:
A labor union is an organization of workers that negotiates with employers over wages and working conditions. A labor union seeks to change the balance of power between employers and workers by requiring employers to deal with workers collectively, rather than as individuals. As such, a labor union operates like a monopoly in a labor market. We sometimes call negotiations between unions and firms collective bargaining.