Your intuition is going in the right direction. Workers, and worker aggregates in the form of unions or other entities, are the supply side for labor. They can

Your intuition is going in the right direction. Workers, and worker aggregates in the form of unions or other entities, are the supply side for labor. They can be a monopoly (indeed, "better wages" and similar demands are expressions of market power). If there is only one demander (employer) for the labor, it would be a monopsony. Like a coal company in a company town.