Lit. “Expounding.” A term used for a commentary written in explanation of any book or treatise, as distinguished from tafsir, which is used only for a commentary of the Qur’an. These expositions are written either in the text, or on the side of the book or treatise they attempt to expound. The term, however generally used for marginal notes is hashiyah. For example, the Tanwiru ‘l-Absur is the matn, or text, of a great work on Muslim laws, written by Shamsu ‘d-Din Muhammad A.H. 995; the Durru ‘l-Mukhtar is a sharh, or commentary written on that work by ‘Ala ‘d-Din Muhammad, A.H. 1088; and the Hashiyah, or marginal notes on these two works, is the Raddu ‘l-Muhtar, by Muhammad Amman.
Based on Hughes, Dictionary of Islam