What does it mean by ethnohistory?

Ethnohistory is an interdisciplinary approach to indigenous, colonial, and postcolonial culture and history. Combining the approaches of history, cultural anthropology, and archaeology, ethnohistory has most often focused on the cultures and histories of the indigenous peoples of settler societies in the Americas, Australia, New Zealand, the Pacific, and South Asia.

Erminie Wheeler‐Voegelin provided the first definition for the society when she described ethnohistory as the “study of identities, locations, contacts, movements, numbers, cultural activities of primitive peoples from the earliest written records concerning them, onward in point of time.

Like anthropologists, ethnohistorians ideally focus on the whole culture of an ethnic group or society as a developing entity over time and space. Even when they lay particular stress on one aspect of the culture, their analysis is still ethnologically oriented by their assumption that no part is to be understood without reference to its place in the whole.

Ethnohistorians have productively analyzed the political economy of colonial empires, the impact of epidemics on indigenous populations, the nature of imperial bureaucracies, indigenous strategies of survival and resistance, and Christian evangelization and indigenous responses, among other topics.
What does it mean by ethnohistory?