1) a person in charge of an auction (auctioneer)
2) a person in charge of a building's cleaning, repairs etc (caretaker)
3) a person in charge of horses; to clean the fur and skin (groom)
4) a person in charge of a library (librarian)
5) a person in charge of money etc belonging to a club or society (treasurer)
the elected head of government in the USA and some other republics; a head of some business companies, colleges, societies etc
chief executive
