"A person living in a region overrun by Muslim conquest who was accorded a protected status and allowed to retain his original faith". According to orthodox Islamic law (Shari'ah), those who are qualified for Dhimmi status within the Muslim society are the free (i.e non-slave) Christians, Jews, and Zoroastrians. Adherents of other religions, as well as those without religion, are asked to convert to Islam; if they refuse, they are to be forced to convert.  However, historically, adherents of Hinduism, Buddhism, Sikhism, and other religions, have lived as Dhimmis within Muslim states.
According to the Qur'an and hadith, Jizyah tax must be paid by the dhimmis as a sign of submission. This gives dhimmis some legal protection in return. As established by the Pact of Omar, dhimmis usually are not allowed to carry arms to protect themselves, serve in the army or government, display symbols of their faith, build or repair places of worship, they must wear distinctive clothing which includes the Zunar (a kind of belt) wherever they go, etc. Many of these laws are still enforced today in Muslim countries, like Egypt and Saudi Arabia, which enforce various aspects of Shari'ah. If the conquered do not wish to pay or convert, their fate may very well be slavery (under which, rape is permitted) or death. The pact also declares that dhimmis are forbidden to ride horses and camels, and may only ride donkeys, and only on packsaddles.