A game is a form of structured play undertaken for enjoyment or entertainment. A game may be played alone or in teams; with one or more opponents; by children or adults; by amateurs or professionals. It can be played with rules or without them; on paper, in a boardroom, on a tabletop, or on a computer; with an audience or by oneself. It can be a complex piece of interactive entertainment such as a video game or a puzzle, or it may be as simple as stacking toys in a bucket to dump them out again.

Despite the enormous popularity and commercial success of games, the concept of game remains relatively vague. This is partly because games can be so diverse and partly because it is not always clear what sort of activity a game represents. Consequently, there are many different definitions of game: Katie Salen defines it as a “system in which players engage in an artificial conflict defined by rules that results in a quantifiable outcome.” Other scholars have focused on the social aspects of games or how they can be used to convey historical information.

One of the key issues is that games have a number of properties that set them apart from other activities: they are inefficient; they impose obstacles that prevent players from reaching their goals by the most efficient means; they are closed systems in which resources and information do not flow outside the game. In addition, they are an activity for which the rules and objectives must be learned.

This can make it difficult for newcomers to understand what games are and how they work. It also makes it hard to define them accurately and objectively. For these reasons, it is often a good idea to base a definition of game on previous research in the field rather than starting from scratch (see for example Bogost 2009). This does not guarantee that the resulting definition will be superior to other ones; however, it makes it less likely to run into problems that others have already solved.

Some scholars have taken a more formal approach to defining games, drawing on the work of Roger Caillois and Bernard Suits. Keith Burgun, for example, defines a game as an activity in which agents compete by making ambiguous but meaningful decisions. Roger Caillois also defined a game as a fun, separate and uncertain activity governed by rules.

The word game is also used as a synonym for contest or competition. For example, someone who is “game for a hike” is willing to take on a challenge that might be dangerous or unpleasant. The phrase is also used to describe a man who would be a good marksman. It is also a common way to refer to wild animals and birds that are hunted for sport or eaten, such as pheasant or rabbit.