Games according to Raph Koster http://www.raphkoster.com/2013/04/16/playing-with-game/
Defining a game is more complex than it sounds. Raph Koster (ref Theory of Fun) contrasts the formal game, a construct that has a series of rules designed for others to follow, and…and play. However, he also suggests that ‘We cannot,ever say what a game is.., because it is different for everyone. To one, the stock market is a game. ….To another, a piece of interactive fiction, and to another, a game of chess. He suggests that most activities could be considered a game if they are approached with a lusory attitude. Bernard Suits called this “a lusory attitude.”
The term ‘Play’however with the advent of serious games
Some people associate “play” with freedom, flexibility, lack of rules. But it is perhaps better to think of “unstructured play” as actually being about manyrules, tons and tons of them, many unstated, often changing on the fly; and “structured play” as being about fewer rules, clearly stated. Calvinball is unstructured; Nomic, funny enough, is highly structured. Both are fertile fields for play.
However some might consider life itself to be a ‘game’ with more complex rules and so the definition of a game and play is subjective.