What does converting to ACC in itunes mean?

I have a rather large music collection in my itunes, but I can't have it in my library unless I also have the files somewhere else on my computer for itunes to locate them from. I wanted to find a way to just move those files into into itunes without having to keep another folder of them for locating because it takes up so much space and if that folder accidentally gets moved I have to relocate every single song. I tried converting one song into ACC and then deleting the original file to see if ACC did the trick, and it still played. So is that what converting to ACC means? That you just permenently move the song into itunes and I could do that to my whole library and delete the original files? HELP!

AAC is just Apples name for the M4P audio format.

When you converted it, it made a copy inside the iTunes folder inside your music folder inside your profile. That is unless you changed the default location to somewhere else.

import all your music into itunes as aac. then move all the originals onto a cd/dvd or external hdd. then you have the space on the computer, and if for some reason it craps itself, you still have all your originals.