Linguistically: It is a sign or mark, and its plural forms are “shurut,” “shara’it,” and “ashrat”. [940] Al-Sihah by Jawhari (3/1136) and Taj al-`Arus by Zabidi (19/405).

Technically: It is something whose absence necessitates the absence of the ruling but whose presence does not necessitate the presence or absence of the ruling of its own accord. [941] Rawdat al-Nazir by Ibn Qudamah (1/179), Al-Furuq by Qarafi (1/110), and Taqrib al-Wusul ila `Ilm al-Usul by Ibn Juzayy, p. 173.