In the pre-Islamic period, the word sunnah was used with the meaning "manner of, acting", whether good or bad. During the early Islamic period, the term came to refer to any good precedent set by people of the past, including the Islamic prophet Muhammad. Under the influence of Al-Shafi'i, who argued for priority of Muhammad's example as recorded in hadith over precedents set by other authorities, the term al-sunnah eventually came to be viewed as synonymous with the sunnah of Muhammad.
The sunnah of Muhammad includes his specific words (Sunnah Qawliyyah), habits, practices (Sunnah Fiiliyyah), and silent approvals (Sunnah Taqririyyah). According to Muslim belief, Muhammad was the best exemplar for Muslims, and his practices are to be adhered to in fulfilling the divine injunctions, carrying out religious rites, and moulding life in accord with the will of God. Instituting these practices was, as the Quran states, a part of Muhammad's responsibility as a messenger of God. Recording the sunnah was an Arabian tradition and, once people converted to Islam, they brought this custom to their religion.
The word "Sunnah" is also used to refer to religious duties that are optional, such as Sunnah salat.
Sunnah (سنة , plural سنن sunan ) is an Arabic word that means "habit" or "usual practice".
Sunni Muslims are also referred to as Ahl as-Sunnah wa'l-Jamā'ah ("people of the tradition and the community (of Muhammad)") or Ahl as-Sunnah for short. Some early Sunnî Muslim scholars (such as Abu Hanifa, al-Humaydî, Ibn Abî `Âsim, Abû Dâwûd, and Abû Nasr al-Marwazî) reportedly used the term "the Sunnah" narrowly to refer to Sunnî Doctrine as opposed to the creeds of Shia and other non-Sunni sects.