noun: an involuntary vibration (as if from illness or fear)
noun: a small earthquake
noun: shaking or trembling (usually resulting from weakness or stress or disease)
verb: shake with seismic vibrations

Ramsay
When a uniform dressed lath is held at the center of gravity and struck, it vibrates freely with a low tremor; when held at the center of velocity and struck at the center of gravity, it vibrates freely, and goes into large sections. But if it be struck at two-thirds of one-third from the other end, its own center of percussion, it has not the least tendency to vibrate. But if it be held at the center of velocity, and at its own center of percussion at the other end, and struck at the center of gravity, these two places will become points of rest, and the lath will move freely in all the other parts. [Scientific Basis and Build of Music, page 93]