chief

/tʃiːf/

A leader or head of a group of people, organisation, etc.

All firefighters report to the fire chief.

The top part of a shield or escutcheon; more specifically, an ordinary consisting of the upper part of the field cut off by a horizontal line, generally occupying the top third.

The principal part or top of anything.

An informal term of address, sometimes ironic.

Hey, chief.