Definitions of captain:

• noun:   a diningroom attendant who is in charge of the waiters and the seating of customers
• noun:   the pilot ins charge of an airship
• noun:   the naval officer in command of a military ship
• noun:   a policeman in charge of a precinct
• noun:   an officer holding a rank below a major but above a lieutenant
• noun:   the leader of a group of people

  Example: "A captain of industry"

• noun:   an officer who is licensed to command a merchant ship
• verb:   be the captain of a sports team
• name:  A surname (very rare: popularity rank in the U.S.: #21684)