What is no oil preesure means

It means do NOT drive the car. No oil pressure is just what is sounds like, and if it's not too late you can get it fixed with possibly a new oil pump, or whatever is causing the lack of oil pressure. Begin by simply checking the oil level on dipstick. If it is low, add to 'full' mark then start it and see if you have pressure then, but it would have to be way low. If that's not the case, shut it off immediately and get it to a shop before you blow your engine, and don't drive it there, no oil pressure will destroy an engine in a matter of seconds.

^^^^ What he said ^^^^ Do not drive it.