a card game that is played by one person using a standard deck of 52 cards, in which the goal is to place all of one's cards in a particular pattern, sequence, or arrangement;
e.g. She was playing a game of solitaire to pass the time.
(noun)
a single gemstone, especially a diamond, that is set into a piece of jewelry alone, or a ring that is set with a single gemstone;
e.g. Her wedding ring was a diamond solitaire that sparkled in the light.