Password

Card Number refers to the eight-digit number that most cards have on the bottom-left corner on the card (certain cards, such as Labyrinth Wall, do not have this card number).

Card Numbers, while serving no real purpose in the actual game, do serve a purpose in the video game. By entering a card number found on any given card (usually in a "Password" selection screen), you may obtain that card for your virtual collection, although various restrictions are placed on this depending on the game. In some games entering the code got you the card for free, while in others you have to pay in-game currency to do so. In most of the latest games, you also have to have the card you're trying to get in your card list, which either involves owning the card, or owning most of the cards in the set the card comes in.

Passcodes are similar to Card Numbers, except they can contain a mix of letters and numbers, and are used in only a handful of games.