<span>The fundamental = 1st harmonic is not an overtone!
Fundamental frequency = 1st harmonic.
2nd harmonic = 1st overtone.
3rd harmonic = 2nd overtone.
4th harmonic = 3rd overtone.
5th harmonic = 4th overtone.
6th harmonic = 5th overtone.</span>
I'm pretty sure it's strings but it could be wrong
