Followers are called Muslims; Muslim is not a religion.
Adjective is Islamic. Muslim is not an adjective.
An Islamist is an adherent of Islamism, or political Islam. Islamists view the Quran as both a political and religious code. Islamist can carry political implications; use with discretion.
Holy book is the Quran, not Qur’an or Koran.
More than 1.6 billion people are followers of Islam.
Major sects are Sunni and Shia.
Sunni is a noun or adjective; the plural of Sunni (n.) is Sunnis.
The majority (85 to 90 percent) of Muslims are Sunni. Sunni Muslims include followers of the Hanafi, Shafi, Maliki and Hanbali schools of jurisprudence and the Salafi movement.
Sunnis are the majority in more than 40 countries, including Afghanistan, Egypt, Indonesia, Saudi Arabia and Turkey.
Shia (“follower”) describes the collective; an individual is a Shiite: They are Shia. He is a Shiite.
Shias include Ithna Asharis (Twelvers), Ismailis, Zaydis, Alevis and Alawites.
The Pew Research Group estimates there are between 154 million and 200 million Shias in the world today.
Between 35 and 40 percent of the world’s Shias (66 to 70 million) live in Iran. Shias make up a majority of the total population in Iran, Azerbaijan, Bahrain and Iraq; between 68 and 80 percent of the world Shia population live in Iran, Pakistan, India and Iraq, all of which have at least 16 million Shias.
There is a sizable Shia population (1 million or more) in Afghanistan, Azerbaijan, Lebanon, Nigeria, Saudi Arabia, Syria, Tanzania, Turkey and Yemen.
The Baha’i in Iran; Kharijites, found in Oman; the Nation of Islam in the United States; and the Druze, found primarily in Lebanon but also in Syria and Israel, are Muslims who cannot be easily classified as either Sunni or Shia.
Sufism has followers among both Shias and Sunnis as well as adherents who identify primarily as Sufi.