Christophe Grandsire writes:
>
> >
> > That is indeed so in most modern formulations of the Special Theory of
> > Relativity. But I'm pretty sure that back when the expression first
> > got popularized, m was used for the 'relativistic mass', i.e.
> >
> >                         m = \gamma m_0
> >
> > where m_0 is the rest mass. With that definition, E = m c^2 is exactly
> > correct.
> >
>
> Except that it's misleading, because most people don't know about the
> difference between rest and relativistic mass and everyone who quotes this
> takes the mass to be the rest mass. So it stays a misquote, even if in the
> mouth of some people it may not be. I may be anal about all this, but to me a
> good scientific quote must be unambiguous and unmisleading.
>

No equation can be unambiguous without stating the meaning of the
variables and constants, though, can it?