In a recent (now locked thread) someone asked what intonation of a piano means. Intonation refers to the relative tuning temperament of the strings (as in the Well-Tempered Clavier). The definition that was provided in the now locked thread really refers to "voicing", not intonation. Unless I'm wrong that is.
I think you are right. The definition of intonation in one of the music dictionaries is: the degree to which the pitch of a note heard is what is correct but not to the degree that the note heard is the wrong note. (that one is sort of weird) Here's an simpler one: A term referring to the proper production of a tone so that it is exactly in tune. To me, voicing means adjusting the hammers to hit the strings a certain way. Pricking the hammers with needles is to soften or scrape the felt so that the sound hitting the strings is less harsh. I think either Horowitz or Rubinstein was particularly picky as to how their pianos were voiced - Zimerman too, I hear. Probably all of the pros are. I’d like to be but don’t have the patience to work on every hammer.
Yes, if someone were singing off-key, you could say the singer had problems with his/her intonation. I drive my piano technician mad with my constant finagling with the piano's voicing. My ears are too sensitive for their own good. :lol: