"Something" is anything that exists; even spacetime, having dimension and certain physical laws, can be considered something. Thus, in the gaping void between galaxies, where there might be one particle per cubic kilometre, one can not legitimately say "There's nothing there". One still does, of course, just as, searching a food cupboard, one might well say the same, meaning "there is no tin of sardines", but this is a mere verbal convenience.
True nothing isn't. It can't even be approached asymptotically, like absolute zero; the absolute best that could be done is removal of matter and energy, gravitation and electric fields; dimension would be unaffected. Perhaps what the universe is expanding into; except that the concept can't really be justified. Hands up those who visualise the expanding hypersphere of the universe moving into a sort of cold, dark vacuum? Wrong. We are not equipped to imagine true nothingness, it is a zen concept, a lack that has to not exist in order that "something" has some meaning.