Music Composers Unite!
Thanks Bob, Lawrence and Teoh for your help. This is what I mean for a serious and grammatically correct definition of terms.
Bob, I agree that tone and tonal are two different concepts, and so they should be, but see below.
Teoh, I think you got it in a nutshell. "Atonal" as a term does derive from the word "tonal" as a concept. Here I think that language and its usage failed us. I find this term quite poor for describing such a marvellous and complex application as tonality with 400 years history.
And Lawrence, you've got it in a nutshell too! If you refer to my explanation of the steritic "a" and the word that follows it as a concept meaning the opposite than the word that follows it, there it is:
Tonal is a positive term
Atonal is a negative term which can only tell us what something is not, but never what it is.
I also find myself in sympathy with the idea of pan-tonal, but given our 20th century music practices and taking into account the East as well as the West hemisphere, I prefer to call modern music pan-intervalic rather than pan-tonal.
I wish I had some more time to carry on but… :-)
But that's just it. Folks can't sign-up for something if they don't know what they are signing up for. "Atonal" (whatever that is) might be too broad a term for a treatise.
OK. Thanks for clearing that up.