Native American identity in the United States is an evolving topic based on the struggle to define "Native American" or "(American) Indian" both for people who consider themselves Native American and for people who do not. Some people seek an identity that will provide for a stable definition for legal, social, and personal purposes. There are a number of different factors which have been used to define "Indianness," and the source and potential use of the definition play a role in what definition is used. Facets which characterize "Indianness" include culture, society, genes/biology, law, and self-identity. An important question is whether the definition should be dynamic and changeable across time and situation, or whether it is possible to define "Indianness" in a static way. The dynamic definitions may be based in how Indians adapt and adjust to dominant society, which may be called an "oppositional process" by which the boundaries between Indians and the dominant groups are maintained. Another reason for dynamic definitions is the process of "ethnogenesis", which is the process by which the ethnic identity of the group is developed and renewed as social organizations and cultures evolve. The question of identity, especially aboriginal identity, is common in many societies worldwide.