A technical term in philosophy derived from the Greek hyle (matter), opposed to ṣūra (form). Usually used in the sense of prime matter, being the third emanated principle after the intellect and the soul in the cosmogonies of Ismaili thinkers such as al-Sijistānī (d. 971) and Nāṣir Khusraw (d. ca. 1088), and also in the Epistles of the Brethren of Purity.
