“Resonance” is a “driven harmonic oscillation“, where the driving force pushes and pulls at, or near, the “resonant frequency” of whatever it is that doing the resonating. The first is that nothing in the world “rings” perfectly, and the second is that every example of harmonic motion you’re likely to come across is actually an example of “damped harmonic motion”. You can make anything bounce around and shake, but “harmonic motion” is something very specific. Harmonic motion is a vibration that takes place at just one frequency. ), but most of the time the oscillation frequency starts getting wonky, the wave stops being pretty (not just one frequency), and trying to induce resonance just sorta stops working.