> > We can use UB to refer to both. :)

> You can, but in the context of the standard, you'd be wrong to do so. Undefined behavior and unspecified behavior have specific, different, meanings in context of the C and C++ standards.

> Conflate them at your own peril.

I think that ryao was not conflating them, but literally just pointing out, as a joke, that "UB" can stand for "undefined behavior" or "unspecified behavior." Taking advantage of this is inviting dangerous ambiguity, which is why ryao's suggestion ended with ":)," but I think that saying that it's wrong is an overstateent.