"John Rumm" wrote in message
o.uk...
Norman Wells wrote:

According to my Dictionary of Science and Technology, which is the only
_definition_ that's been provided in this thread, it's 'the quantity of
matter in a body'. As such, it _is_ a measure of the number of
elementary particles. It cannot be otherwise.

Here you go, half a dozen other definitions:

http://en.wikipedia.org/wiki/Mass

Did anybody address the question of just what is an elementary particle, and
what the mass of one is?

("there isn't such a thing" is entirely acceptable :-) )