Definition of captain :
1. A head, or chief officer
2. A military leader; a warrior.
3. A person having authority over others acting in concert; as, the captain of a boat's crew; the captain of a football team.
4. An officer in the United States navy, next above a commander and below a commodore, and ranking with a colonel in the army.
5. By courtesy, an officer actually commanding a vessel, although not having the rank of captain.
6. Chief; superior.
7. One in charge of a portion of a ship's company; as, a captain of a top, captain of a gun, etc.
8. The foreman of a body of workmen.
9. The master or commanding officer of a merchant vessel.
10. The military officer who commands a company, troop, or battery, or who has the rank entitling him to do so though he may be employed on other service.
11. To act as captain of; to lead.
schoolmaster, senior pilot, head waiter, headman, passkey, police captain, master key, victor, professional, maitre d'hotel, guide, tribal chief, Old Man, skipper, maitre d', police chief, superior, sea captain, headwaiter, lead, command, cap, precede, chieftain, original, master copy, passe-partout, operator
aeronaut (part of speech: noun)
master (part of speech: noun)
landlord, authority, maestro, guru, head, senior, principal, mother, sire, abbot, titleholder, commandant, governor, ruler, dean, squire, director, mahatma, proprietress, chief, manager, commander, president, headmaster, star, landlady, leader, headmistress, quartermaster, kingpin, officer, executive, mandarin, proprietor, master, Lord
sailor (part of speech: noun)
director (part of speech: noun)