Solitaire is a card game designed for one player. Unlike games where you compete against opponents, in solitaire you play alone, trying to arrange all the cards in a particular pattern or order according to specific rules.

The most famous version involves dealing cards into seven columns and trying to move them into four piles, one for each suit, arranged from ace to king. You flip cards, shift them between columns, and search for moves, sometimes winning and sometimes getting stuck with no legal moves left. Players often discover that winning requires both luck in how the cards fall and skill in choosing which moves to make.

Before computers and phones, people played solitaire with actual decks of cards, often to pass time or think through problems while their hands stayed busy. The game became so popular on early computers that millions of people learned to use a mouse by dragging virtual cards around the screen.

The word is sometimes used more broadly to describe anything done solo. It can also describe a single gemstone set by itself in a ring, standing alone rather than surrounded by other stones.