A leader.
One who conducts or leads; a guide; a director.
A person who conducts an orchestra, choir or other music ensemble; a professional whose occupation is conducting.
An ideal of a ring that measures how far it is from being integrally closed
A grooved sound or staff used for directing instruments, such as lithontriptic forceps; a director.
A person who takes tickets on public transportation and also helps passengers.
Something that can transmit electricity, heat, light, or sound.
A supreme commander of the armed forces of a country, especially one who is also a political leader.