The term Dhimmitude is derived from Dhimmi, which means a non-Muslim living in an Islamic country. The Merriam-Webster Online Dictionary has defined it as "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.
The law professor Antoine Fattal offered the following analysis of dhimmitude after close study of Islamic law:
Dhimma (or dhimmitude) ... is one of the results of the jihad or holy war. ; Connected with the notion of jihad is the distinction between dar al-harb (territory or "house" of war) and dar al-islam (house of Islam). The latter includes all territories subject to Muslim authority. It is in a state of perpetual war with the dar al-harb. The inhabitants of the dar al-harb are harbis, who are not answerable to the Islamic authority and whose persons and goods are mubah, that is, at the mercy of Believers. However, when Muslims are in a subordinate state, they can negotiate a truce with the harbis lasting no more than ten years, which they are obliged to revoke unilaterally as soon as they regain the upper hand, following the example of the Prophet after Hudaibiyya
The dhimmi, we might say, is a second-class citizen. If they [the ruling Muslims] tolerate him it is a calculated step, whether because they cherish the hope of converting him or for material reasons, because they force him to shoulder virtually the entire burden of taxation. They provide a place for him in the state, but not without reminding him continually of his inferior status. They prevent him from occupying high positions in society, and if by merit or intrigue he manages to climb to such places everything conspires to relegate him once again to obscurity. If the dhimmi acquires an independent legal status or privileges associated with his personal position, if he is permitted even his own courts, it is only because he cannot share with the Faithful the advantages of their own justice, which is essentially religious. In no case is the dhimmi the equal of a Muslim. He is condemned to social inequality and forms part of a despised caste: inequality so far as his personal rights are concerned, inequality in taxation, and inequality before the law, since his testimony is neither accepted by the Muslim courts of justice nor even, for the same minor crime, is the punishment the same ... No social relationship, no fellowship is possible between Muslims and dhimmis.