OK. Keep thinking that. With a blitz, all you need to do is create a mismatch, overload a gap, or bring more to a side than they can block. Before someone on the other side can react, you're through. My example already is outside your definition. Two linemen and two LBs rush. This is a blitz. Five guys with their hands on the ground - not a blitz.
Your definition is a nice generalization, but not accurate. No definition will be accurate, as long as it attempts to be specific in quantities. No way.