Labor Union. A labor union is an organization that represents workers in collective bargaining agreements. A collective bargaining agreement is also known as a labor contract. Individual bargaining amounts to one worker asking his boss for a raise. If a worker bargains as an individual, he is at a disadvantage. If all the workers in a the factory are members of a labor union, the labor union bargains for all of them, collectively. This means that if the boss agrees to give them a raise, all the workers get the raise, collectively. Members of a labor union are also permitted to go on strike, if negotiations fail. Labor unions in the U.S.A. are regulated by a government organization called the NLRB (National Labor Relations Board).