What is Chief ?
Chief is (adj) most important He’s the chief planner in the local authority. What is the chief cause of air accidents? Synonym principal(noun) 1. a person in charge in a group of people or in a business He’s been made the new chief of our department. The fire chief warned that the building was dangerous. 2. the leader of a tribe All the chiefs came together at a meeting.
source: Easier English, Student Dictionary Upper Intermediate Level