I am quoting a dictionary of the English language, and we are both using that same language right now. Other than the occasional quaint term such as "tossing a wowser", the meanings of most words are identical in both the US and Oz. Were it otherwise, you would not feel insulted when I state that you're a throughgoing bonehead.
And you are very carefully failing to quote what it *does* say about the word "denatured"; if anything.
Let's see: the OP is presumably from the US, David answered his question correctly using US terminology (assuming there *is* any difference in terminology, which you have yet to demonstrate), and you think starting an argument about possible overseas definitions has any relevance to *anything*!?
If you're going to answer a question from the US in terms that aren't used in the US, all you're doing is muddying the water; not proving how cool you are, or even providing useful information.
Now that's just plain dumb.
Definition #2 is the one that specifically applies to the denaturing of alcohol -it says so right there- and that's the subject at hand, so *of course* it's the one that applies. (The words "especially to add methanol to (ethyl alcohol)." should have been your clue.)
(A) You have still not demonstrated that the word "denatured" applies to the treatment of Ethyl alcohol only in the US. (Lack of evidence is not evidence.)
(B) You only have to use the relevant definitions if you intend to provide relevant information. Heck, if you just want to demonstrate that trolls exist everywhere, you're perfectly free to post your answers in Swahili.
But don't expect anyone to bother with translating.