Centre of Oscillation

That point in the axis or line of suspension of a vibrating body, or system of bodies, in which, if the whole matter or weight be collected, the vibrations will still be performed in the same time, and with the same angular velocity, as before.

Centre of Percussion, in a moving body, is that point where the percussion or stroke is the greatest, and in which the whole percutient force of the body is supposed to be collected. Percussion is the impression a body makes in falling or striking upon another, or the shock of bodies in motion striking against each other. It is either direct or oblique; direct when the impulse is given in a line perpendicular to the point of contact; and oblique when it is given in a line oblique to the point of contact.