Face cards are the jacks, queens and kings of a standard deck: the cards that carry a portrait. A 52-card deck holds 12 of them, three in each suit. In North America they are called face cards; in the UK the traditional name is court cards. Aces are not face cards, even though they often rank highest.
In casino games, face cards matter for scoring. They count as 10 in blackjack, where a face card with an ace makes blackjack, and as zero in baccarat. Several faces also have nicknames. The jack of spades and jack of hearts are drawn in profile and known as the one-eyed jacks; together with the king of diamonds they make up the one-eyed royals. The king of hearts, who appears to push his sword into his own head, is the “suicide king”.
Picture cards in game rules
Face cards drive several popular side bets and variants, so check each game’s paytable for how picture cards are scored and paid.