- Kaaba
- The sanctuary at Mecca, where the Arabs worshipped tribal gods before Islam; cleared of its idols when the Prophet Muhammad entered Mecca in 630.
- Quraysh
- The leading tribe of Mecca, into whose Banu Hashim clan the Prophet Muhammad was born; its leaders opposed his preaching.
- Hijra
- The Prophet Muhammad's migration from Mecca to Yathrib, renamed Medina, in 622; year one of the lunar Islamic calendar.
- Umma
- The community of believers; the first Muslim community was the one the Prophet Muhammad led at Medina.
- Quran
- The revelations the Prophet Muhammad received, given their standard written form under the third caliph Uthman.
- Hadith
- The reported sayings of the Prophet Muhammad; with the Sunna, the second source of guidance after the Quran.
- Sunna
- The practice of the Prophet Muhammad; with the Hadith, the second source of guidance after the Quran.
- Tawhid
- The oneness of God, at the centre of the Prophet Muhammad's preaching.
- Khalifa
- Caliph: successor or deputy of the Messenger, the political and community leader of the Muslims, not a prophet.
- Rashidun
- The rightly guided: the first four caliphs, chosen by the community, Abu Bakr, Umar, Uthman and Ali, 632 to 661.
- Umayyad
- The hereditary caliphate Muawiya founded at Damascus in 661, which sent the Sindh expedition and fell to the Abbasids in 750.
- Abbasid
- The caliphate that rose from Khorasan, overthrew the Umayyads in 750 and built Baghdad in 762; the Mongols ended it in 1258.
- Shia
- The party of Ali: those who held that leadership of the Muslims belonged to Ali's line; Husayn's death at Karbala is their central tragedy.
- Sunni
- The majority of Muslims, who accepted the caliphs chosen by the community as legitimate.
- Kharijite
- One of those who rejected the arbitration after Siffin and broke away from Ali; one of them killed Ali in 661.
- Ghulam
- A slave soldier, bought as a boy, trained to fight and loyal to his master alone; Turkish ghulams rose to command and then to rule.
- Sultan
- Power, authority: the title of a ruler holding power in the caliph's name; Mahmud of Ghazni was the first ruler called Sultan.
- Ghazi
- A warrior for the faith; Mahmud of Ghazni styled himself one.
- Tengri
- The sky, worshipped by the Turks of the steppe before Buddhism, Manichaeism and then Islam reached them.
- Khorasan
- The old region of northeast Iran, with Herat and Balkh in Afghanistan and Merv in Turkmenistan; the Abbasids rose from it.
- Transoxiana
- Mawarannahr, the land beyond the Oxus: Uzbekistan and Tajikistan today, with Bukhara and Samarkand.
- Dhimmi
- A protected non Muslim subject who paid the jizya and kharaj, kept his religion and was exempt from military service; Qasim applied it in Sindh.
- Jizya
- A tax per head on adult male non Muslims under Muslim rule, the price of the protection covenant.
- Kharaj
- Land revenue on agricultural produce, paid by Muslim and non Muslim cultivators alike.
- Manjaniq
- A catapult or trebuchet for breaching walls, used at Debal in 711.
- Chachnama
- The chief account of the Arab conquest of Sindh, first in Arabic and put into Persian by Muhammad Ali Kufi of Uch in 1216; also the Fathnama i Sind.
- Jyotirlinga
- One of the twelve most sacred Shiva shrines, of the pillar of light; Somnath is one.
- Kitab ul Hind
- The Book on India, Al Biruni's study of India in eighty chapters, written in Arabic about 1030.
- Antyaja
- Those outside the four varnas, as Al Biruni describes them in the Kitab ul Hind.
- Turushkadanda
- A tax named in the Gahadavala grants whose purpose is debated: a levy to fight the Turks, or to pay them.