This document provides an overview of key terms in Islam, including: - Muhammad, the prophet who first received revelations from the Quran and established Islam. - The Quran, the holy book of Islam believed to be the verbatim word of God revealed to Muhammad. - The hijra, Muhammad's emigration from Mecca to Medina in 622 CE, which marks the beginning of the Islamic calendar. - The Five Pillars of Islam, the core rituals and duties of Muslims including confession of faith, prayer, fasting, pilgrimage, and almsgiving. - Tawhid, the Islamic concept of divine unity and oneness of God and community.