What is the difference between Wait and Synchronization point?

There are 2 types of Synchronization.
Local and Global.
For an object there is a Global synch time (20 seconds by default)(Available under File->Settings->Run in QTP 9.0) and additionally we can set individually the synch time for a particular object.

Hence total synch time is = Local + Global synch time.

In wait there is no Global concept and it is local to that object only.

Another key difference is: Suppose we have put a wait for 10 seconds then the application would wait for 10 seconds unconditionally. But say if we put a synch point of 10 secs say for an object to appear(local) and default Global synch time is 20 seconds, then total synch time for that object is 20 + 10 =30 seconds, but in case the object would appear in 15 seconds itself, even though the total synch time was 30 seconds, the script would proceed to the next task.