What’s the difference between apple juice and apple cider?

The main commercial apple juice product in parts of Europe is a cider that contains alcohol (hard cider).  In North America, however, the term, cider, can mean an alcoholic or an unfermented drink depending upon the area of the country.  In the U.S., in the Northeast and Midwest, the term apple cider  refers to a drink made by grinding and pressing whole apples.  Minimal filtering is done, so the resulting liquid is dark or light brown and has pulp in it.  On the other hand, the term apple juice applies to a clear liquid. However, in other sections of  the U.S., apple juice refers to both the clear beverage and the unfermented cider, and apple cider  means a fermented (alcoholic) drink. 
 
Source(s): 
The Oxford Companion to Food by Alan Davidson, 1999.
Store interview:  Manager, Jewel Food Store, Niles, IL, 4/24/09.
Wisconsin Apple Cider Safety Site