Definition
The volume of navigable atmosphere above a defined geographic area, divided by regulation into classes and special-use areas, each with specific entry requirements, equipment requirements, pilot qualifications, and operating rules.
Plain English
The sky, treated as something with rules. It is split into zones, and each zone has its own requirements about who can fly there, what equipment they need, and how they must operate.
Context Anchor
Pilots encounter airspace during flight planning, on aviation charts, near airports, during training flights, and whenever deciding where they may safely and legally fly.
Derivation
From 'air' plus 'space' — literally the space made up of air. The aviation use adds the idea that this space is mapped, classified, and regulated, not just open sky.
Why Pilots Care
Knowing airspace rules prevents violations that can lead to enforcement action or safety issues.
Intuition Check
Do not think of airspace as just empty sky. In aviation, airspace is sky with boundaries and rules attached to it.
Example Sentence 1
Before the flight, the instructor reviewed the airspace along the route so the student knew where a radio call would be required.
Example Sentence 2
Entering busy airspace near the airport required radio contact with controllers.