- Roman law2
- Rāfiʻī, ʻAbd al-Karīm ibn Muḥammad, 1162-1226. ʻAzīz ʻalá al-Wajīz2
- Sakhāwī, ʻAlī ibn Muḥammad, 1163?-1245. ʻUmdat al-mujīd fī al-naẓm wa-al-tajwīd2
- Samarqandī, Muḥammad ibn Ashraf, active 13th century. Risālah fī ādāb al-baḥth2
- Sayings2
- Scholasticism2
- Science, Medieval2
- Sefirot (Cabala)2
- Shāfiyah (Ibn al-Ḥājib, ʻUthmān ibn ʻUmar)2
- Shīʻah2
- Shīʻah--Customs and practices2
- Siddur2
- Sifra2
- Signed bindings2
- Spiritual exercises2
- Spirituality2
- Statutes2
- Summa theologica (Thomas, Aquinas, Saint)2
- Sundials2
- Symbolism2