Whereas the word 'solitaire game' in context with a game originally simply meant that a game is designed to be played by one player only, the game 'solitaire', especially peg solitaire is such an old game that the word 'solitaire' has become closely associated with this special game.
Games that are similar to peg solitaire are therefore called solitaire-type puzzles.

'Solitaire-type puzzles' typically consist of

• a board with holes or indentations and
• a set of pegs or marbles which we will call 'tokens'

At the start the tokens usually are on the board in a certain starting configuration. Through a sequence of moves the player is asked to reach a certain end configuration. Often this configuration consists of an empty board or of a board with only one token left.

Solitaire-type puzzles are closely related to solitaire card games.

Marbles is a notable example of a puzzle of this type.