Plain English Meaning
The weight of the aircraft itself with all its built-in equipment and fluids in place, but before adding fuel you can actually burn, passengers, baggage, or cargo.
Full Definition
The weight of an aircraft including the airframe, engines, all permanently installed equipment, unusable fuel, and full operating fluids (engine oil, hydraulic fluid, and other system fluids required for operation). It does not include usable fuel, payload, or crew.
Context Anchor
Seen in aircraft weight-and-balance records, the Pilot’s Operating Handbook, and loading calculations before a .