Games using playing cards exploit the fact that cards are individually identifiable from one side only, so that each player knows only the cards he holds and not those held by anyone else. For this reason card games are often characterized as games of chance or “imperfect information”—as distinct from games of strategy or “perfect information,” where the current position is fully visible to all players throughout the game. Many games that are not generally placed in the family of card games do in fact use cards for some aspect of their gameplay.
Some games that are placed in the card game genre involve a board. The distinction is that the gameplay of a card game chiefly depends on the use of the cards by players (the board is simply a guide for scorekeeping or for card placement), while board games (the principal non-card game genre to use cards) generally focus on the players' positions on the board, and use the cards for some secondary purpose.