"Dungan" is the name given in Central Asia to the Hui people of the Chinas. They are Muslims, and are thus distinguishable from the Han Chinese, who are mostly Confucian, Buddhist or Religion of Light.
Their area of habitation stretches from Beihanguo through northern Tibet, Uyguristan, Altai and southwestern Mongolia to Turkestan, and they are related to other Hui in other parts of China. There is some terminological confusion here, as the term "Dungan" is only used of the northwestern Hui, but other groups of Chinese Muslims in other parts of the Chinas are also known as Hui.
In Central Asia, the Dungans are known for making tasty food, and besides their semi-Chinese style traditional costume this is the one recognisably different thing about them. They have mostly assimilated culturally to the Turkestanis, Uygurs or others around them.
The Dungan people formerly called themselves Zhongyuanren, "the people of Zhongyuan", not Dungans; however, they have been known as Dungans by the Central Asian peoples from time immemorial, and have more or less adopted this exonym for themselves.