العرف
al-ʿUrf
The common and approved custom of a people, used in the absence of a contrary ruling as a basis from which law is derived
What it means
ʿUrf means what is known and approved among people. Jurists accept it as a source of rulings where no text or other source decides the matter. The Quran tells the Prophet to “enjoin what is customary and good” (7:199), and the word there is ʿurf. Custom helps fix matters the texts leave open, such as what counts as reasonable maintenance in a marriage or the usual meaning of a word in a contract. Its limits are clear: a custom that contradicts the Quran or the Sunnah has no force. The jurists’ maxim holds that custom may serve as a basis for judgement.
Often misunderstood as
That custom can override the Quran, when the law accepts custom only where the texts are silent.
Term and Arabic as listed in Ismail al Faruqi, Toward Islamic English (International Institute of Islamic Thought, 1995), p. 53, listed as AL 'URF. The definition is restated here.