ask bon scott! – damn, he's dead, so you can't. to me it always meant just "rock" as in rock'n roll, but you never can tell, what these hard rockers have on their minds when writing their lyrics. it's a song by ac/dc, by the way.
here's the chorus,so you can judge for yourself:

"Let there be sound,"
there was sound.
"Let there be light,"
there was light.
"Let there be drums,"
there was drums.
"Let there be guitar,"
There was guitar.
"Ohh Let there be rock."