The term multiculturalism has a range of meanings within the contexts of sociology, political philosophy, and colloquial use. In sociology and in everyday usage, it is a synonym for "ethnic pluralism", with the two terms often used interchangeably, and for cultural pluralism in which various ethnic groups collaborate and enter into a dialogue with one another without having to sacrifice their particular identities. It can describe a mixed ethnic community area where multiple cultural traditions exist (such as New York City or London) or a single country within which they do (such as Switzerland, Belgium or Russia). Groups associated with an indigenous, aboriginal or autochthonous ethnic group and settler-descended ethnic groups are often the focus.

In reference to sociology, multiculturalism is the end-state of either a natural or artificial process (for example: legally-controlled immigration) and occurs on either a large national scale or on a smaller scale within a nation's communities. On a smaller scale this can occur artificially when a jurisdiction is established or expanded by amalgamating areas with two or more different cultures (e.g. French Canada and English Canada). On a large scale, it can occur as a result of either legal or illegal migration to and from different jurisdictions around the world.

In reference to political science, multiculturalism can be defined as a state's capacity to effectively and efficiently deal with cultural plurality within its sovereign borders. Multiculturalism as a political philosophy involves ideologies and policies which vary widely. It has been described as a "salad bowl" and as a "cultural mosaic", in contrast to a "melting pot".