Plain English Meaning
The airplane is pointing upward — the nose is tilted up above the horizon line you'd see straight ahead.
Full Definition
A flight attitude in which the airplane's nose is pitched above the horizon, so the longitudinal axis points upward relative to level flight.
Context Anchor
Used when describing airplane control and performance, especially during maneuvers such as a chandelle, takeoff, climb, slow flight, and landing flare.
Derivation
“Nose” means the front of the airplane, and “high” means raised. “” originally carried the idea of posture or ; in , it means the airplane’s position relative to the horizon, not someone’s mood.