Resonance is what happens when something vibrates or responds powerfully because it matches a particular frequency or strikes a deep chord. In physics, resonance occurs when you push something at just the right rhythm to make it vibrate strongly, like pumping your legs on a swing at exactly the right moments to go higher and higher. Each push adds to the previous one, building up energy.

Musical instruments rely on resonance to make sound. When you pluck a guitar string, the hollow body of the guitar resonates, amplifying the vibration into the rich sound you hear. A tuning fork will start vibrating if another tuning fork of the exact same pitch is struck nearby, because the sound waves match its natural frequency.

The word also describes an emotional or intellectual connection. When a story has resonance with you, it touches something deep inside, like reading about a character who feels exactly what you've felt. When a teacher's words resonate with students, the ideas don't just get heard but truly understood and felt. A speech might resonate with an audience because it expresses what they've been thinking but couldn't put into words.

Something can also resonate in a broader sense when it creates lasting echoes or effects. A historical event might resonate through the decades, continuing to influence how people think and act long after it happened.