Being a bumpkin, I first thought a well tempered clavier was a harpsichord or piano that was well tuned to the 12-tone tempered octive.
But the post indicates that it is a collection of musical compositions for multiple keyboard instruments. Why was the term “well tempered clavier” chosen.
And Wikipedia mentions “short tempered clavier”. Hmm.
“Why was the term “well tempered clavier” chosen.”
They weren’t yet using the “equal temperament” system we use now, but they had developed some precursors of that system to allow keyboardists to play in any key without having to retune the instrument for every song. The work contains songs in every one of the 24 keys, so that type of tuning system was a necessity in order to be able to play this kind of collection.
Because to make an instrument that plays pure harmony in each key signature of composition that might be written, there would have to be a key lever/string activator for every one of 51 frequencies within each octave on the instrument. Otherwise to have only 12 piano keys comprising a perfect octave, for the frequency of each of the strings, some temporizing must be achieved . Any piano tuner can tell you that.