Span of management refers to the number of subordinates that a manager can effectively supervise and manage. It is also known as span of control or span of supervision. A wider span of management means that a manager has more subordinates reporting to them, while a narrower span of management means that a manager has fewer subordinates reporting to them. The optimal span of management can vary depending on factors such as the complexity of tasks, the level of employee experience, and the manager's leadership style.