(Islam) a tradition based on reports of the sayings and activities of Muhammad and his companions
Sunnah, Sunna, hadith (noun)
(Islam) the way of life prescribed as normative for Muslims on the basis of the teachings and practices of Muhammad and interpretations of the Koran
the collected sayings and actions of Muhammad and his companions as related by eyewitnesses, used to determine the Sunna (Muslim way of life).
A ḥadīth is a saying or an act or tacit approval or disapproval ascribed either validly or invalidly to the Islamic prophet Muhammad. Hadith are regarded by traditional Islamic schools of jurisprudence as important tools for understanding the Quran and in matters of jurisprudence. Hadith were evaluated and gathered into large collections during the 8th and 9th centuries. These works are referred to in matters of Islamic law and history to this day. The largest denominations of Islam, Sunni, Shiʻa, and Ibadi, rely upon different sets of hadith collections. Clerics and jurists of all denominations classify individual hadith as sahih, hasan and da'if. However, different traditions within each denomination, and different scholars within each tradition, may differ as to which hadith should be included in which category.