AXIS, in Mechanics. The axis of a balance is that line about which it moves, or rather turns about. Axis of oscillation, is a right line parallel to the horizon, passing through the centre about which a pendulum vibrates.
Axis in Peritrochio, one of the six mechanical powers, consisting of a peritrochium or wheel concentric with the base of a cylinder, and moveable together with it about its axis.
Axis, in Optics, is that particular ray of light coming from any object which falls perpendicularly on the eye.
Axis, in Architecture. Spiral axis, is the axis of a twisted column drawn spirally in order to trace the circumvolutions without. Axis of the Ionic capital, is
a line passing perpendicularly through the middle of the eye of a volute.
Axis of a Vessel, is an imaginary right line passing through the middle of it perpendicularly to its base, and equally distant from its sides.