The melting pot is a metaphor for a [[wiktionary:heterogeneous heterogeneous]] society becoming more [[wiktionary:homogeneous homogeneous]], the different elements "melting together" into a harmonious whole with a common culture. It is particularly used to describe the assimilation of immigrants to the United States. The melting-together metaphor was in use by the 1780s.
More at: Melting pot
More at: melting pot