Plain English Meaning

Three invisible lines through the middle of the airplane that it pivots around. Roll happens around the nose-to-tail line, pitch around the wingtip-to-wingtip line, and yaw around the up-and-down line.

Full Definition

Three imaginary straight lines passing through an aircraft's center of gravity, each at right angles to the other two, around which the aircraft rotates in flight. The longitudinal axis runs nose to tail (rotation around it is roll); the lateral axis runs wingtip to wingtip (rotation around it is pitch); the vertical axis runs top to bottom (rotation around it is yaw).

Context Anchor

Seen in discussions of flight controls, aircraft , and airplane .