the presiding officer of a meeting, committee, board, etc.

the administrative head of a department in a high school, college, or university.

someone employed to carry or wheel a person in a chair.

to act as or be chairman of (a meeting, committee, etc.).

noun

administrator , captain , chair , chairperson , chairwoman , director , introducer , leader , moderator , monitor , president , presider , principal , prolocutor , speaker , spokesman , toastmaster