define Play, Game, and Simulation

We live in the world which is already made before we were born. Languages are also part of the world, and we are just naturally using languages without thinking about where it is from and either it is really right or wrong sometimes. As professor Dr. Smith suggested, what is definition of the words Play, Game, and Simulation?
Based on my experiences, I think the word "Play" is from real enjoyment. When I was really young, the word 'Play' meant meeting friends and going to playground with the friends and family to me, and it was always fun and made me laugh a lot. Now, I have learned lots of things in the world, and I know that the word 'Play' has lots of meaning. We just say "Play" game, "Play" piano, he is "Play"boy...etc. Why people add the word "PLAY" when they do game and some certain other things like doing tennis? I think playing game, music, sport, and even love(relationship) are for your enjoyment and making yourself happy.
Second, I think the word "Game" is for fun, but it is more like a competition then just fun at the same time. In Korea, we have lots of "GAME ROOM" which have lots of computers or play stations, and you pay for playing games in there. I did some simulation gun shot games, and Starcraft, World of warcraft. I just spent so much time and money to stay there because it made me so fun to compete with people who i do not know. Not only about web games, but also about "Game" in a lot of area such as sports game, it is more like competition( I am sure you have seen beiging olympic GAME in this year!) ,and it gives you fun when you watch or play it.
Related with those words Game and Play, the word Simulation is fake, but it feels like real when you "PLAY GAME". As i said, I was doing some simulation games, and I had really fun ( I spent at least 3-4 hours for this.) I know those games are not real, but it made me think that the main character I chose is me. So I got a bit mad if my character died becuase of the game. That would be funny for the others, but I think it is the power of "Simulation".
As a result, you will have fun becuase it feels real and exciting becuase of competition if you "PLAY SIMULATION GAME"