Inner mongolia has 2 different meanings across 2 categories:
an autonomous region of northeastern China that was annexed by the Manchu rulers in 1635 and became an integral part of China in 1911
An East Asian region, south of Outer Mongolia (the present Mongolian republic), with closely related native Mongolian population, mostly north of the Great Wall, which however became part of the Chinese empire, and later an autonomous region in the People's Republic of China, comprising several northern provinces