> No One knows that´s the point. Is truth a constant or a personal definition! From the begining of times to now, no One knows.

I don't think this is a well defined question. Definitions aren't found in nature or the laws of science, but objects that we define and introduce into a logical context. There may be multiple, contradictory definitions of a word. That is fine, as long as you pick one, and you're clear about which one you picked.