Chain of command is
1. The line of authority extending from upper organizational levels to the lowest levels, which clarifies who reports to whom.
2. The succession of commanding officers from a superior to a subordinate through which command is exercised. Also called command channel.
Chain of command is a set of relationships that indicates who directs which activities and who reports to whom.
The vertical structuring of the organization results in a decision-making hierarchy that shows who is is in charge of each task, of each specialty area, and of the organization as a whole. Levels of management are established from bottom to top in the organization. These levels create the chain of command, or hierarchy of decision-making levels in the company.
Chain of command refers the channel in which communication, coordination, and control flow through the various levels of management to subordinates.