Technically nothing. Cider is made with wine yeast usually, not a beer yeast, even though it's more often compared with beer.
Usually the difference is alcohol content and cider is most frequently carbonated but apple wine is frequently not carbonated. I don't think there is a hard cut off point where a cider becomes a wine though. A wine will have less of a fruit-flavour typically.
For my apple wine I used "champagne yeast", and although I didn't measure with a hydrometer so don't know for sure, I suspect it has about a 13% alcohol content.
There's also something called cyzer which is an apple melomel (wine made with honey as a primary food for the yeast).