The "American Dream" concept springs from the early start of America, a new world filled with the promise of hope, opportunity, and freedom from persecution and oppression. It has evolved to mean that, as Americans, we are given a wealth of opportunity. We are constantly told that, with hard work and perseverance, we can do or become anything that we want to do or become. The sad reality, however, is that there are and have always been obstacles in the path to success. Many people, such as Gatsby, have found ways around those obstacles. He wanted to be powerful, to be successful, and he did what it took to have what he wanted. However, in the end, what he wanted is what made him a tragic figure. He achieved wealth and power, but Daisy was never going to leave Tom for him. She was willing to use him for what he had to offer her - love and material wealth - but he was still nothing more than a poor soldier in her eyes. This is the tragic flaw that is most commonly associated with the American Dream. People believe in it so strongly that they are willing to sacrifice morality in order to achieve it, only to find that once they have whatever it is they thought that they wanted, it isn;t all that it seemed it would be.

I think the American Dream continues to vary.

Some common attributes I have seen in reference to this phrase include:

• A quest to overcome suppression or oppression.
• A measure of success whether materially, relationally, or in terms of contribution toward a cause or quest.
• A search for significance
• A desire to not be put into a box in terms of life purpose.
• The pursuit of life, liberty and happiness.

I see you are reading The Great Gatsby. This novel addresses your question accurately. However, I do not think Gatsby embodies the American Reality, although he does deal with an American's DREAM. As you may be considering a paper, think about how Gatsby meets or fails to meet my above listed qualities.

In the words of James Truslow Adams in his book The Epic of America:

The American Dream is "that dream of a land in which life should be better and richer and fuller for everyone, with opportunity for each according to ability or achievement. It is not a dream of motor cars and high wages, but a dream of social order in which each man and each woman shall be able to achieve the fullest stature of which they are capable of, and be recognized by others for what they are, regardless of the circumstances of birth or position.

I don't know that there is any one "dictionary" definition of the American dream, but it generally means something like this.  The American dream refers to the idea of getting ahead in life and doing it on your own.  Americans believe that they can go as far in life as their determination will get them.  So the American dream is to work hard and get ahead in life.

Getting ahead usually refers to having material things and relatively high status in your community.  If you think about this in terms of Gatsby's situation, he has clearly achieved the American dream in terms of having a lot of material possessions and in terms of having people look up to him.