Linked from
The 15 pages that link to Axis of rotation, each with the reason it gives.
TorqueRelated: Torque is defined relative to an axis, so changing the axis can change its value.
Moment of inertiaRelated: The moment of inertia is defined relative to this chosen line.
Oblate spheroidRelated: The ellipse’s shorter axis becomes the spheroid’s polar axis.
GimbalRelated: The arrangement of rotation axes determines a gimbal’s allowed motions.
Wheel and axleRelated: The wheel and axle share an axis that constrains their rotation.