The starting pitcher plays the entire game and does not allow the opposing team to score a single run. Opposing players can reach the bases and have hits, but there are no runs scored so it will end something like this: 5-0. If two pitchers combine for the effort, the team can be accredited a shutout, but statistically neither pitcher will record the shutout in the books which looks like this: ShO or SHO.
The No Hitter
This one is easy - no hits. Also called a No-No, this feat is often also a shutout because it is extremely difficult to reach home plate without any hits. Steals, walks and errors can attribute to a run by the opposition, but it is rare - it most recently happened on July 27, 2011 when the Los Angeles Angels of Anaheim won 3-1 against the Cleveland Indians thanks to Ervin Santana. The pitcher plays the entire game and cannot give up a single hit allowing a runner to reach base. Players at the plate may advance to first base via a walk, a hit batsman or an error, but that's it.
The Perfect GameIt is just that - absolutely perfect. Not a single hit, walk, run, error or hit batsman... only strikeouts and great plays. Nobody gets to first base, to make it clear. The pitcher often faces some full counts, loads up on strikeouts and he plays the full game. There's only been 22 of them ever to be recorded in Major League Baseball history, and two in the last two months. This is not just about the pitcher however, this is a lot to do with the supporting cast. In every perfect game, there are always moments where it can be taken away by just one bad pitch or one mishandled catch, but somebody always comes through . It's the ultimate team effort and one of the greatest accomplishments in sport.