If you've been around the writing world for awhile, you will have picked up on some of the slang that is used. Acronyms abound, just like everything else. The acronym ARC stands for Advanced Reader Copy.
These copies are kind of like a unrevised draft of the book. These are what's handed out to people who are paid to read them, or those who volunteer to read them (for the free book!), and then give their opinion -- and write a review perhaps -- so that the final copy can have positive comments on the cover.
You'll find that many of these ARC books have spelling errors, grammatical errors, and sometimes even messed up formatting. One such book I got to read didn't have the illustrations, only the words.
I think it would be kind of a mixed feeling upon receiving the first copy of your story. You think, "Wow! It's in print!" and then you see the first mis-spelled word. Perhaps it's while perusing this copy that you realize a scene should have been written differently, or could have done a better ending. At this point, there is still the possibility of minor corrections. I'm not sure about major ones, but definitely minor ones. If you are self publishing, you can have as many different versions of this 'rough copy' as you want to pay for. In the traditional publishing world though, you don't.
That is also another reason to be part of a critique group, or as I've heard some authors, a collection of 'readers' who are paid to go through and make sure everything is spotted early on.
Even if your book does make it to final publishing and gets out on the market with some kind of error, don't think it's the first. I have a friend who has written and self published. He was amazed at the mistakes that survived his many different edits. Fortunately, those errors were changed in a second run, as he sold out the first printing.
So take heart -- should your work make it through to the printed page with typos -- there is always the next run...