Solitaire, also called Patience, often refers to single-player card games involving a layout of cards with a goal of sorting them in some manner. However it is possible to play the same games competitively (often a head to head race) and cooperatively. The term solitaire is also used for single-player games of concentration and skill using a set layout of tiles, pegs or stones rather than cards. These games include Peg solitaire and Shanghai solitaire.

These games typically involve dealing cards from a shuffled deck into a prescribed arrangement on a tabletop, from which the player attempts to reorder the deck by suit and rank through a series of moves transferring cards from one place to another under prescribed restrictions. Some games allow for the reshuffling of the deck(s), and/or the placement of cards into new or "empty" locations.

There are many different solitaire games, but the term "solitaire" is often used to refer specifically to the most well-known form, called "Klondike". Klondike and some other solitaire games have been adapted into two-player competitive games. See List of solitaire card games for more.

There is a vast array of variations on the solitaire/patience theme, using either one or more decks of cards, with rules of varying complexity and skill levels. Many of these have been converted to electronic form and are available as computer games. Basic forms of Klondike solitaire and FreeCell come with every current installation of Microsoft Windows. Many software solitaire collections can be downloaded from the internet at no charge.