Definition
An instruction from air traffic control directing the pilot to set a specific four-digit code on the aircraft's transponder, which then transmits that code to ATC radar so the flight can be identified and tracked.
Plain English
When ATC says 'squawk,' they're telling you to enter a number into your transponder so they can see you on their radar screen with that code attached.
Context Anchor
Heard in ATC instructions during IFR clearances, departures, radar contact, and when a controller needs you to change your transponder code.
Derivation
The term comes from 'Parrot,' the World War II codename for the early IFF (Identification Friend or Foe) transponder system. Operators talked about making the 'parrot squawk,' meaning getting it to transmit its identifying signal. The nickname stuck and is still standard ATC phraseology today.
Why Pilots Care
Proper squawking gives ATC positive radar contact, enables traffic separation, and prevents the flight from being treated as unidentified or lost.
Intuition Check
Squawk does not mean to complain here. In this context, it means to set or operate the transponder as instructed by ATC.
Example Sentence 1
Cleared for takeoff, the pilot read back, 'Squawk 4271, runway 27, cleared for takeoff.'
Example Sentence 2
The pilot set the transponder to squawk 1200 while remaining in the traffic pattern.