What is a formal complaint made by an employee about their employer called?

A formal complaint made by an employee about their employer is referred to as a grievance. This term signifies that the employee has a specific issue or concern usually related to employment conditions, treatment, workplace policies, or labor conditions that they believe must be addressed by the employer or management.

The grievance process is a crucial element in many workplaces, as it allows employees to voice their complaints formally, which can lead to resolution or further investigation into the matter. This formal procedure not only provides clarity about the issues raised but also ensures that there is an official record of the complaint, which can be significant for both parties.

While the other options—dispute, feedback, and request—might relate to interactions between employees and employers, they do not capture the essence of a formal complaint in the same way that "grievance" does. A dispute typically involves a disagreement that may not necessarily be raised formally, feedback is generally unsolicited or informal communication about work performance or conditions, and a request implies a desire for something without the implication of a complaint or grievance. Thus, "grievance" is the most appropriate term for a formal complaint made by an employee.