military officer,
officer any person in the armed services who holds a position of authority or command; "an officer is responsible for the lives of his men"
saclant,
supreme allied commander atlantic commanding officer of ACLANT; a general of the United States Army nominated by the President of the United States and approved by the North Atlantic Council
Commander is a naval rank which is also sometimes used as a military title depending on the individual customs of a given military service. Commander is also used as a rank or title in some organizations outside of the armed forces, particularly in police and law enforcement.