Resonance is a word that, for lack of a better term, resonates with me ... perhaps because my mental ear has heard it used in technical conversation as well as in literary and psychological contexts. Set up an electrical circuit with a coil and a capacitor, and you've got a "resonator". Energy pours back and forth between the components at a magical rate, a time constant defined by inductance and capacitance. Tickle the circuit by applying a signal voltage, and when you get near the resonant frequency the amplitude becomes huge.
Precisely the same phenomenon happens with sound in a cavity of the right size and shape. A little input that repeats at the right pace will build up into a gigantic sloshing wave, an earsplitting organ pipe whistle. Or consider the Bay of Fundy, a natural resonator that almost matches the frequency of lunar tides --- and therefore amplifies that tidal signal to huge proportions.
And in the exotic subatomic realm of high energy physics, a resonance is a particle --- albeit one that's so unstable it only survives for a glimpse of an moment before it falls apart into the pieces that made it. Send two particle beams crashing into each other, and when their relative energies match a resonance they interact violently.
Just so in human conversation, when ideas mesh ....