Potentiometer

noun

1. An instrument for measuring an unknown voltage by comparison to a standard voltage.
2. A three-terminal resistor with an adjustable center connection, widely used for volume control in radio and television receivers.
3. An instrument used for measuring the difference of electrical potential between two points.
4. An instrument for measuring or comparing electrial potentials or electro-motive forces.
5. a user-adjustable variable resistor that functions as a voltage divider.