What is the origin and meaning of the title of Lorraine Hansberry’s play A Raisin in the Sun? What does it stand for and which theme(s) of the play does it reflect?

The title comes from a Langston Hughes poem about dreams and what happens to our dreams when they fail to become reality, "What happens to a dream deferred?/Does it dry up/like a raisin in the sun?" THe younger family have the dream of transcending racism and owning their own house. They desperately want a piece of the "American Dream". THey continually need to water and nurture their dream lest is dry up and shrivel up like a raisin in the sun.