Sufism or Tasawwuf (Arabic: تصوف), is defined as the inner mystical dimension of Islam. Practitioners of Sufism (Tasawwuf), referred to as Sufis , often belong to different ṭuruq or "orders"—congregations formed around a grand master referred to as a Mawla who maintains a direct chain of teachers back to the Prophet Muhammad (PBUH). These orders meet for spiritual sessions (majalis) in meeting places known as zawiyahs, khanqahs, or tekke. Sufis strive for ihsan (perfection of worship) as detailed in a hadith: "Ihsan is to worship Allah as if you see Him; if you can't see Him, surely He sees you."