The OP and some of the links in this thread have a lot of terminology about tuning that is a bit short on precise definitions. Okay, since I made some progress

The OP and some of the links in this thread have a lot of terminology about tuning that is a bit short on precise definitions. Okay, since I made some progress with violin, I understand that the intervals of a minor third (three semi-tones), major third (four semi-tones), a fourth (five semi-tones), a fifth (seven semi-tones), a sixth (nine semi-tones), and an octave (12 semi-tones) consist of two frequencies that are ratios of small whole numbers and where the interval of a semi-tone is the ratio of two frequencies of approximately 2^(1/12). Commonly violinists call these intervals, especially the major third, fifth, and octave, perfect. And I understand that setting the frequency of the first A above middle C to 440 Hz and all the semi-tone frequency ratios to 2^(1/12) is tempered tuning. Ah, now I see in the OP: "Equal temperament, the modern and usually inappropriate system of tuning used in western music, is based on the twelfth root of 2. The ratio of frequencies for each semi tone is equal to the twelfth root of two." So, what I called tempered tuning the OP calls "equal temperament". Is that the same as well temperament? For all the other terminology about approaches to tuning, e.g., mean tuning, I have no clear definitions. E.g., it appears that the OP is still vague on just what equal tuning is. Is there a source with clear definitions?