What players of the game engage in: Behavior according to certain rules, that
characterize the game, that serves some purpose, like amusement, instruction,
learning or deceit.
The term "games" is used for many different activities, and in
various more specific senses. It is difficult to define it in such a way that
the definition accounts for all usages. However, it is taken as more specific
than the similar term play, in that a game is a game, and in
particular that game, because of its satisfying certain rules, that one has to
know in order to be able to play the game.
There is a mathematical theory of games, that relates to games like chess,
bridge and poker, and more broadly to strategic behavior in economics and
politics, that involves reasoning about possibilities, probabilities and
pay-offs, and strategies with which one can optimize one's winnings or
minimize one's losses.
There is also a tragic site to games: Very many of the games people play
are played while believing them to be something other than games. Indeed, the
common social roles - father, mother, boss, clerk, manager, leader, follower,
doctor, nurse and so on - tend to be mostly games that the actors play while
believing or pretending that the way they play it and think of it is the right
way to act out and believe in such a role.