Which term defines the act of entering a transponder code as provided by ATC?

The term that defines the act of entering a transponder code as provided by ATC is "squawk." In aviation, squawking typically refers to the process of inputting a specific code into the aircraft's transponder, which then transmits identification information to air traffic control radar systems. This code helps ATC track and identify each aircraft within their airspace.

Understanding this term is important for pilots since proper communication with ATC includes using the correct squawk code when instructed. The other options do not accurately capture the specific action of entering a transponder code: "transmit" refers to sending a signal or message, "relay" typically means passing on information from one party to another, and "broadcast" involves sending out signals that can be received by anyone within range, which is different from the precise action of squawking a specific transponder code.