A key difference between Blackjack and Spanish 21 is that all 10s are removed from the deck in Spanish 21. A Blackjack occurs when the first two cards that are dealt equal 21 a combination of a face card (Jack, Queen, or King) and an Ace (which can have a value of 1 or 11, depending on your hand).
Napoleon Bonaparte so enjoyed playing vingt-et-un, the French card game, that he taught it to his English jailers when he was exiled on Saint Helena after losing at Waterloo.