Plain English Meaning
If you can't land from the approach, this is the pre-planned route that tells you how to climb away safely and where to go next.
Full Definition
A published set of instructions a pilot must follow when an instrument approach cannot be completed to a landing. It specifies a climb, a track or heading, and a holding fix or other safe maneuvering point, designed to keep the aircraft clear of terrain and obstacles while transitioning from approach to climb-out.
Context Anchor
Seen on instrument approach charts and used during instrument flying when the runway is not in sight, the aircraft is not in a safe position to land, or a controller tells the pilot to stop the approach.
Derivation
"Missed" here means the approach was not completed — the landing was missed, not that the pilot did anything wrong. "Approach" is the descent toward the runway. So a missed approach procedure is simply the published plan for what to do when an approach doesn't end in a landing.
Why Pilots Care
Executing the published procedure keeps the aircraft clear of terrain and obstacles while maintaining separation from other traffic.
Intuition Check
A “missed approach” does not necessarily mean the pilot made a mistake. It means the landing cannot or should not be completed, so the pilot follows the published plan to climb away safely.
Example Sentence 1
Reaching minimums without seeing the runway, the pilot began the missed approach procedure: climbing straight ahead to 2,000 feet, then a left turn direct to the holding fix.
Example Sentence 2
The crew reviewed the missed approach procedure before starting the ILS approach in case visibility fell below minimums.