A card game is any game played with cards. There are many different types of card games. Some of these card games do not even use a regular 52 card deck; they have special decks of cards for some games like Uno and Old Maid, which are 2 games for kids.
My favorite card game when I was a kid was War. The object of the game was to win all the cards. Players would split the deck of cards and without looking at the top card at the same time both players lay them out and the higher card wins. Today you can find some casinos that have turned this card game for kids into a casino game. The casino version of this card game is much easier to find in online casinos then in the land based casinos.