CMC meaning in Military and Defence ?

Command master chief petty officer (CMDCM) is an enlisted rating in the United States Navy and U.S. Coast Guard, as well as the Japan Maritime Self-Defense Force.

In the U.S. Navy, the command master chief petty officer is the senior enlisted advisor at a command and as such works as a liaison between the commanding officer and the enlisted ranks, serving as the senior enlisted leader. In this capacity, the CMDCM assists the commanding officer in issues of quality of life, discipline, training, and morale. Collectively, the CMDCM, commanding officer, and executive officer are referred to as the "big three".