In what circumstances can I use the word chief?
You usually use the word "chief" when it's someone's title: chief officer, editor-in-chief, chief justice, chief of police, chief executor officer, etc. It's a title that shows high importance and rank. If you watch many cop shows or crime shows, you will hear the word "chief" used often. Ex: Anna Wintour is the editor-in-chief of Vogue Magazine. Ex: Chief, you gotta come and see this. Ex: He is the chief of police in a large city.