The drone terminology and definitions is an online glossary for drone and quadcopter enthusiasts.
This the term used to describe the controller used by the pilot to operate the quadcopter.
An RC transmitter is usually a hand held device that is used to control the vehicle. The transmitter is inside a casing and has an aerial and joysticks to control the movement of the quadcopter.
A typical RC transmitter has 4 to 6 channels with at least 4 of them allowing you to move the vehicle proportionally to the movements of the control sticks so the more you push on the stick the more control the vehicle will receive from that stick.