Comment by shabble

People from a musical, non-signals background tend to use 'harmonics' as a synonym for 'overtones' or 'partial tones', which is where the confusion arises, I suspect.

There's a measure -- inharmonicity[1] -- of how far the actual overtones of a particular instrument differ from their theoretical fundamental multiples.

[I suspect you already know this. This reply is probably for others' benefit]

[1] https://en.wikipedia.org/wiki/Inharmonicity