One of the pure tones that makes up a complex tone.
"Partial" is the term generally preferred today by both scientists and music-theorists. An older term which is essentially synonymous and still found often is "overtone".
One thing to be aware of, especially in older German music-theory treatises, is that "overtones" are generally labeled beginning with the first partial above the fundamental -- the word "overtone" itself indicates that the fundamental is not an overtone. Thus:
In most acoustic musical instruments, the frequencies of the partials are integer multiples above the fundamental. This creates a harmonic series, and helps to reinforce the sensation of the fundamental pitch.
The tonalsoft.com website is almost entirely the work of one person: me, Joe Monzo. Please reward me for my knowledge and effort by choosing your preferred level of financial support. Thank you.