After conquering "China proper", the Manchus identified their state as "China" (中國, Zhōngguó; "Middle Kingdom"), and referred to it as Dulimbai Gurun in Manchu (Dulimbai means "central" or "middle," gurun means "nation" or "state"). The emperors equated the lands of the Qing state (including present day Northeast China, Xinjiang, Mongolia, Tibet and other areas) as "China" in both the Chinese and Manchu languages, defining China as a multi-ethnic state, and rejecting the idea that "China" only meant Han areas. The Qing emperors proclaimed that both Han and non-Han peoples were part of "China." They used both "China" and "Qing" to refer to their state in official documents, international treaties (as the Qing was known internationally as "China" or the "Chinese Empire") and foreign affairs, and "Chinese language" (Dulimbai gurun i bithe) included Chinese, Manchu, and Mongol languages, and "Chinese people" (中國之人 Zhōngguó zhī rén; Manchu: Dulimbai gurun i niyalma) referred to all subjects of the empire. In the Chinese-language versions of its treaties and its maps of the world, the Qing government used "Qing" and "China" interchangeably.
What does China mean?
Middle Kingdom