What is an Elite card in Hearthstone?
Solution 1:
jw013 is correct. An elite card is one that you can only have one copy of in a deck. As the game currently stands, all elite cards are legendary rarity, and all legendary rarity cards are elite, however in a future update it is possible they may add an elite card that is non-legendary, or a legendary card that can have two copies and is thus not elite, since the elite label is a separate piece of code from the legendary rarity label.