She wasn't defining the word! Besides, her example doesn't stray far from the earlier conception of the word "open-minded".
She said first one had to be "open-minded," then she clarified that she meant "shut out all distractions." In a way, yes, she was defining the word, or at least defining how she used it (like when Snicket says, "_____, which here means ______"). And, I have never heard of (nor can I find) a definition that means "shutting out all distractions," in fact, that's closer to the definition of close-minded. Even if it is an earlier conception of the word, (a) it doesn't matter now, as that is no longer the meaning, and (b) how many people have even heard of that meaning, and would be able to know that was the meaning she meant?