Does the piano belong to string or percussion family?

"Percussion. The piano makes sound when small hammers hit the strings inside the piano. This hitting action classifies it as percussion."

And this answer is backed up by which dictionary?

According to the Free Online Dictionary (see related link) a piano is defined as:

piano¹
n pl -anos
(Music / Instruments) a musical stringed instrument resembling a harp set in a vertical or horizontal frame, played by depressing keys that cause hammers to strike the strings and produce audible vibrations See also grand piano, upright piano
[short for pianoforte]

According to the Real Academia Española (the most prestigious and highly respected dictionary in Spain) a piano is defined as:

piano.
(De pianoforte).


1. m. Instrumento musical de cuerda provisto de un teclado, cuyo accionamiento permite golpear las cuerdas metálicas mediante macillos forrados de fieltro, y de pedales que hacen possible la variación de la intensidad del sonido.


(Instrumento musical de cuerda = Stringed musical instrument). This would mean that it is in the string family.