Diaspora refers to a large group of people who may share a national or regional origin, but for a variety of reasons, are living outside of this traditional homeland. Diasporic populations are often outnumbered in their new nation of residence. Diaspora was initially used to describe the migrations of Jewish people after the fall of Jerusalem in the sixth century B.C.E. It has since been used to describe other instances of mass migration or forced relocation. Diasporic populations often have strong social and cultural ties to their homeland, but may also have multiple cultural identities.

Throughout global history, there have been hundreds of migration movements, which created and continue to create diasporic populations. Many diasporas have been traumatic. The Jewish diaspora consisted of centuries of Jewish migration, often because of historical expulsion and discrimination. The African diaspora refers to the large populations of African people brought against their will to the Americas through the institution of slavery. The Irish diaspora occurred due to famine and other poor economic conditions, which forced many Irish people to move to North America and Europe. The Armenian, Palestinian, and Syrian diasporas emerged because of conflict. However, not all diasporas have been the result of traumatic events in the home country. For example, between the eighth and 11th centuries, Vikings from Scandinavia spread their population and culture across the Northern Hemisphere in what is now described as a diaspora.

There are several types of diasporas, usually defined by the reason for leaving the diasporic population’s homeland. They are classified as victim, imperial/colonial, trade, or labor diasporas. Victim diasporas are the result of the expulsion of a group from a region. Imperial or colonial diasporas are the result of political expansion. Trade diasporas are the result of business activities. Labor diasporas are the result of a global pursuit for work.

The African Diaspora involved both voluntary and involuntary movement of Africans and their descendants to various parts of the world during the modern and premodern periods, including people who were enslaved and shipped to the Americas via the Atlantic slave trade between the 16th and 19th centuries.​

Populations living in diaspora frequently maintain strong cultural ties to their homeland and their community members. These links serve to emphasize their membership in their ancestral ethnic or religious community. However, members of populations in diaspora also participate and create ties within the overarching cultural group they find themselves in. This can lead to a dual identity, where both cultural or religious contexts affect the way the individual perceives themselves.