I do not think it means, what you think it means.
At the beginning of every random team game I play, I can almost guarantee one of my teammates will say, “rush?”, “RUSH!”, or other versions of the same with various typos. “rush/” “rish/”, “tidj?” (if they are one key to the right on their keyboard) etc.
I am probably straining at gnats here, but I don’t think 90% of these people know what a rush is – there is a difference between a rush and concentrating on tier one units. As I understand it, a rush is when you sacrifice your econ to get units out onto the field before your opponent. Six pooling, or a six raxx would be examples of this. I very rarely see anyone actually rushing in the games I play, as it significantly hinders your econ. If you fail at rushing, your opponent is going to have more resources and wipe you out quite handily.
Most of the games I play have a lot of early aggression; usually with zealots, zerglings, marines, marauders, etc. These games often depend on who wins the early conflicts, but it is, in my opinion, definitely not a rush. I don’t remember the last time I actually “rushed”.
Even today, about 15 minutes into a 3v3, I noticed an opponent’s pylon in my teammates base. I pinged and warned him about it, then my other teammate replied, “he wants to rush you later.” It seems, then, that this word can mean anything from what I consider a rush to sneaking units into a base.
I am probably expecting too much from the battle.net community :-)
Am I completely wrong here? What do you consider a rush?