Plain English Meaning
Knowing how much fuel you have, where it sits in the airplane, how fast you're using it, and how its weight shifts as it burns off — and making decisions accordingly.
Full Definition
The active planning, monitoring, and control of an aircraft's fuel load before and during flight to ensure the airplane remains within weight and balance limits, has sufficient fuel to reach the destination with required reserves, and maintains acceptable center of gravity as fuel is burned from the tanks.
Context Anchor
Seen during preflight planning, weight and balance calculations, fuel stop decisions, and in-flight fuel checks.
Derivation
Fuel comes from an Old French word meaning for feeding a fire. Management comes from words connected with handling or controlling something. Together, the meaning points to actively handling the fuel , not just having fuel in the tanks.