Plain English Meaning
Parts of the sky and ground around your airplane that you simply cannot see from where you sit, because the airplane itself is in the way.
Full Definition
Areas around an aircraft that a pilot cannot see from the cockpit due to obstructions such as the airframe, wings, fuselage, engine cowling, window posts, or other structural components. These regions hide other aircraft, terrain, or obstacles from view during normal scanning.
Context Anchor
Pilots deal with blind spots during visual scanning, taxiing, turns, , and before changing direction on the ground or in the .