A = negation of T = theism O = horizontal equality
This symbol is nicknamed A/T.
More tha 80 official languages and many dialects use the letters A+T as the root letters of the word ATheist.
Look at this multilingual slide-show to find your language:
The discussion is open now:
"DO WE NEED AN UNIVERSAL ATHEIST SYMBOL".
Many grupos and individuals have already adopted the one I am proposing here.
Please be open minded and exercise your free thought :-)
And do not think of this symbol as opposed to the religious symbols it is more close to de PEACE (hippy) symbol and the utopian ANARCHIST one.