It's a phrase we hear a lot: "The American Dream." What is it today compared to prior years, and is it even possible anymore?

Curiosity contributor Susan Sherwood traced the roots of the American Dream and found that its definition may now be changing.

The original "American Dream" dates back to 1931, when James Truslow Adams wrote about it in The Epic of America. It stood for a chance at prosperity and happiness for every American. New specifics were added in different eras. In 1935, the Social Security Act sought to protect people from poverty. Franklin Roosevelt’s 1941 pre-war State of the Union address identified four freedoms Americans would fight for: freedom of expression and worship and freedom from fear and want.

Post-war, the G.I. bill helped add home ownership to the American Dream. In 1944, about 100,000 single-family homes were built; in two years, there were almost one million. By the late 1950s, homes contained televisions and refrigerators and a car in the driveway. During this era, higher education came to the masses. By 1947, about half the country’s college students were ex-military. Compared to the pre-war era, by 1965 the number of college graduates had doubled [source: Kamp].

The original American Dream connoted prosperity. It involved hard work and the opportunity to achieve a higher financial position than one's parents. Is that possible now? According to the U.S. Census, homeownership for 2010 was 66.9 percent; lower than in 2000, representing a small but steady decline since the middle 2000s. Currently, corporate investment and manufacturing often opts to locate outside the U.S., reducing certain job sectors [source: Zakaria]. Homeownership and a stable income, then, may not be as easily attainable today.

But are homes and income the current American Dream? In 2011, MetLife's annual general population survey uncovered significant differences between today's outlook and yesterday's. Only 41 percent considered the American Dream an important goal. In fact, materialism was down: Almost 75 percent believed they had the necessities, up from almost 60 percent the previous year. In fact, income and financial success were last on a list of American Dream components; first was a sense of personal fulfillment. Although the original American Dream may be difficult now, many Americans have shifted to pursuing meaningful relationships and achieving private goals.