To tremble means to shake with small, rapid movements that you can't fully control. Your hands might tremble when you're nervous before giving a speech in front of the class. Your whole body might tremble when you step outside on a freezing winter morning without a coat. Sometimes people tremble with strong emotion: fear can make your knees tremble, excitement can make your voice tremble, and even anger can cause trembling.

The shaking of trembling is usually gentle and quick, different from the violent shaking of an earthquake or the deliberate shaking you do when mixing up chocolate milk. When an old building trembles during a storm, you can feel it vibrating slightly. When a small animal trembles in your hands, you can sense its tiny, rapid movements.

Tremble can also describe something that quivers or wavers. A leaf trembles in the breeze. A singer's voice might tremble on a difficult high note. The word captures that quality of small, unsteady movement that can show vulnerability or instability, whether in a person, an object, or even in someone's voice.