The word Islam comes from the Arabic root s-l-m, a family of words associated with peace, safety and wholeness. The related word salām means peace, while the familiar greeting as-salāmu ʿalaykum means “peace be upon you.” This shared linguistic root explains why the word Islam is frequently translated as peace.
The words are related, but they are not interchangeable. Islam derives more directly from aslama, meaning to submit, surrender or yield oneself. In its religious context, Islam means submission to the will of God. A Muslim is one who submits.
Submission is expressed physically in Muslim prayer through prostration. The Arabic verb sajada means “to prostrate,” and sujūd is the act of prostration. The word masjid, commonly translated into English as “mosque,” comes from the same root, s-j-d, and means “a place of prostration.”
The language therefore brings together related but distinct concepts: peace, submission and prostration. Peace is associated with the root of Islam; submission is the word’s more direct meaning; and prostration is one physical expression of that submission. What Is Islamophobia | Definition, Debate, and Canada
In practical terms, Islam has two principal branches: Sunni and Shia. The division began over who should lead the Muslim community after Prophet Muhammad’s death (PBUH) Sunnis accepted leadership established through consultation and communal agreement shūrā, while the Shia believed that prophet Muhammad’s (PBUH) rightful successor was his cousin and son-in-law Ali, and that legitimate leadership continued through Muhammad’s family. They accept substantially the same Qur’anic text, although they differ in some readings and interpretations, and they rely upon different hadith collections and religious authorities. These differences developed into distinct doctrines, laws and practices.
Some Sunni and Shia scholars have regarded members of the other branch as heretics—or even as non-Muslims who have corrupted Islam.
To a non-Muslim, Sunni and Shia Islam may appear identical; to their most committed adherents, the questions separating them concern legitimate authority, authentic revelation and who has corrupted the religion itself.