The chief of a tribe is its leader. Sitting Bull, chief of the Sioux tribes of the Great Plains
Principal or most eminent in any quality or action; most distinguished; having most influence; taking the lead; most important; as, the chief topic of conversation; the chief interest of man
a person who exercises control over workers; "if you want to leave early you have to ask the foreman"
Chief is used in the job titles of the most senior worker or workers of a particular kind in an organization. the chief test pilot. = head
The chief cause, part, or member of something is the most important one. Financial stress is well established as a chief reason for divorce The job went to one of his chief rivals. = main, principal
The head or leader of any body of men; a commander, as of an army; a head man, as of a tribe, clan, or family; a person in authority who directs the work of others; the principal actor or agent