Difference between save and apply button?

i get confuse in apply and save button. whether Save will save the settings. Apply will save and apply the settings or apply will save the setting for instance or what?

What is the difference between save and apply?

The difference is quite simple: Apply means the changes will be applied and you will remain within the area where you are. Save means the changes will be applied (saved) and you will exit to the main area you are in.

What does the save button do?

It's to save your progress. Normally when your in the middle of doing one of the sections you may decide to come off the computer and do something else for a while well if you hit the submit button it will save your work but also provide you with an error “if you didn't complete the section”.

This is a good explanation, it's for joomla 1.5 but it's the same principle:

http://www.ostraining.com/blog/joomla/joomla-save-and-apply-buttons/