In aviation terminology, what does "squawk" refer to?

In aviation terminology, "squawk" refers specifically to the code assigned to aircraft transponders for identification by air traffic control (ATC). When pilots are instructed to "squawk" a particular code, they are being asked to set their transponder to transmit that specific identification code. This allows ATC to track and identify the aircraft on radar, improving situational awareness and enhancing safety in crowded airspaces. The transponder works by sending out a response signal when it is interrogated by radar, and this response includes the squawk code, which corresponds to that particular flight.

The other options describe different aspects of aviation but do not accurately define "squawk." The altitude of an aircraft is described in feet or meters above sea level, while the route taken refers to the flight path or the waypoints an aircraft follows. The number of passengers onboard is simply a count and does not relate to the aviation term "squawk." Understanding the function of a squawk code is fundamental for effective communication and operations within the airspace system.