The Exception that Proves the Rule

[Frylock]

@John_W.Kennedy

I’m not sure what you mean here. If you mean that you want proof that this is the answer to the original question of what the idiom means, well that is the matter being discussed. If, on the other hand, you are merely asking whether the word “prove” has that meaning in English, well, yes, it does, as can be seen in any adult dictionary, and has had it since the middle ages. (The OED lists it as branch II.)

The former.

[BabyBlues]

Exception that proves the rule

This site shows the origin of the phrase. I found it very clarifying. As this phrase always confused me as well. Some of the statements of others touched on the same info.