| Term | Definition |
| Qur'an | The sacred book of Islam received as a series of revelations to Muhammad. |
| Hadith | A traditional report about a reputed saying or action of the prophet Muhammad. |
| Sura | A chapter of the Qur'an. There are 114 total. |
| Fatiha | The first sura of the Qur'an, or opening, which reveals the essence of the Qur'an. |
| Sunnah | The behavior of the prophet Muhammad, used as a model in Islamic law. |
| Muezzin | One who calls the people to prayer from a high place. |
| Caliph | In Sunni Islam, the successor to the prophet. |
| Shirk | The sin of believing in any divinity except the one God. |
| Kufr | The sin of atheism. |
| Jinn | An invisible being of fire. |
| Ummah | The Muslim community. |
| Shari'ah | The divine law. |
| Ulama | The influential leaders in traditional Muslim society, including spiritual leaders, imams, teachers, state scribes, market inspectors, and judges. |
| Imam | In Shi'ism, the title for the person carrying the initiatic tradition of the Prophetic light. |
| Mahdi | A spiritual and temporal leader who will rule before the end of the world and restore religion and justice. |
| Jihad | Holy war. |
| Mujahid | A selfless fighter in the path of Allah. |
| Fana | The complete denial of self and the realization of God that is one of the steps taken by the Muslim Sufi (mystic) towards the achievement of union with God. |
| Murshid | A spiritual teacher, in esoteric Islam. |
| Shaykh | A spiritual master, in esoteric Islam. |
| Barakah | (Mysticism) The spiritual wisdom and blessing transmitted from master to pupil. |
| Tariqa | An esoteric Sufi order. |
| Dhimmi | A person of non-Muslim religion whose right to practice that religion is protected within an Islamic society. |
| Shahadah | The central Muslim expression of faith: "There is no God but God," and Muhammad is the messenger of God. |
| Fatwa | A legal opinion issued by an authority according to a particular school of law. |
| 'Ashura | A festival celebrated on the 10th day of Muharran. It is the most important day of Muharran for Shi'a Muslims, as it commemorates the death of Husayn. |
| Zakat | Spiritual tithing. |
| Ramadan | The ninth month of the Muslim year, during which strict fasting is observed from sunrise to sunset. |
| Hajj | The holy pilgrimage to Mecca. Muslims are expected to make this pilgrimage at least once in their lifetime. |
| Dhikr | In Sufism, a form of devotion in which the worshiper is absorbed in rhythmic repetition of the name of God or his attributes. |
| Arafat | A sacred site on the pilgrimage. This field is said to be the place where Adam and Eve were taught that humans are created solely for the worship of God. |
| Zam-Zam | A holy well in Mecca from which Hajjis take holy water. |
| Greater Jihad | The inner struggle for faith. |
| Lesser Jihad | The external, physical struggle for faith that often implies fighting. |
| Hijab | The veiling of women for the sake of modesty. |
| Ijtihad | Reasoned interpretation of sacred law by a qualified scholar. |
| Ka'bah | A 15 meter high black stone, draped in black silk, engraved with sacred names of Allah. Pilgrims walk around it seven times until they reach the center and touch Ka'bah itself. |
| Bilal | Among early converts to Islam. When his master tried to whip him into renouncing, he only said, "No God but God," repeatedly. He became a companion of Muhammad. |
| Night of Ascension | A night when Muhammad is said to have ascended through the seven heavens to the far limits of the cosmos, and thence into the Divine Proximity. There he met prophets and teachers from Adam to Jesus, saw paradise and hell, and received the great blessings. |
| Hijrah | Muhammad's migration from Mecca to Medina. |
| Sunni | a follower of the majority branch of Islam, which feels that successors to Muhammad are to be chosen by the Muslim community. |
| Rightly Guided Caliphs | (Rashidun) In Sunni Islam, refers to the first four Caliphs.
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| al-Azhar | A great university and mosque built in Cairo in 972 CE. |
| Shi'a | The minority branch of Islam, which feels that Muhammad's successors where 'Ali and a series of Imams. |
| Sufism | The mystical path of Islam. |
| Dervish | A Sufi ascetic. |
| Rabi'a | A famous eighth century Islamic mystic saint woman from Iraq. |
| Junayd of Bagdad | Taught the need for constant purification, a continuous serious examination of one's motives and actions. He counseled veiled speech to those who had become one with God. |
| Mansur al-Hallaj | The most famous case of a God-intoxicated individual announcing his ascension. When asked his name he responded, "I am God." |
