What's the difference between apple cider and apple juice?  It could be: 
(a) Cider is raw squeezed apple juice that hasn't been filtered or pasteurized, while juice is filtered, pasteurized and vacuum-sealed to make it last longer,

OR

(b) Nothing; it's just a marketing ploy to sell more liquid apple extract during holiday seasons. 
Because of lax legal definitions, it depends on the bottler and the area in which it's sold. #food