Plain English Meaning

A push or pressure on a spinning gyro that tries to tilt it. Instead of tilting where you push, the gyro reacts a quarter-turn later around its spin.

Full Definition

A force applied to a spinning gyroscope that attempts to change the orientation of its spin axis. Because of gyroscopic precession, the gyro responds to a deflective force not at the point where the force is applied, but at a point 90 degrees ahead in the direction of rotation.

Context Anchor

Seen in discussions of gyroscopic precession, especially how a spinning propeller can affect aircraft handling when its angle is changed.

Derivation

From Latin 'deflectere,' meaning 'to bend aside' or 'turn away.' A deflective force is one that tries to bend or turn the gyro's spin axis away from its current orientation.