Harmonics: OVERTONE; especially : one whose vibration frequency is an integral multiple of that of the fundamental b : a flutelike tone produced on a stringed instrument by touching a vibrating string at a nodal point

basically, when you hit a harmonic (by lightly placing your finger on a certain area of a string), it creates a pitch that resonates with the vibration of the entire instrument. they are innate within each stringed instrument and to me it sounds as if the instrument is rejoicing - that it feels free to express what it was created for.

this seems so inadequately described in words, but i love the feeling when someone says something that feels like they've hit a harmonic in me. it doesn't happen very frequently but when it does, it just feels *right.*