A melting pot is a monocultural metaphor for a heterogeneous society becoming more homogeneous, the different elements "melting together" with a common culture; an alternative being a homogeneous society becoming more heterogeneous through the influx of foreign elements with different cultural backgrounds. It can also create a harmonious hybridized society known as cultural amalgamation. In the United States, the term is often used to describe the cultural integration of immigrants to the country. A related concept has been defined as "cultural additivity."
The melting-together metaphor was in use by the 1780s. The exact term "melting pot" came into general usage in the United States after it was used as a metaphor describing a fusion or mixture of nationalities, cultures and ethnicities in Israel Zangwill's 1908 play of the same name.