The American Dream is based upon the notion that America is seen as a land of opportunity. According to James Truslow Adams, who was the first person to use this phrase, the American dream is
"That dream of a land in which life should be better and richer and fuller for every man, with opportunity for each according to his ability or achievement."
This means that people who are coming to America from other countries are looking for a better life. They are looking for an opportunity to use their skills and fulfill their dreams, whether that be to become a singer, actor, or attend college. The America dream means that people will be able to make a living doing what they love for work.