Sunna (plural sunan) is an Arabic word which means: “habit” or “usual practice or manner of acting (whether good or bad, i.e. do-s and don’t-s). In Islamic terms it means the traditions and practices of Hazrat Mohammad (founder of Islam) that are to be followed by Muslims. These are believed to be based on the verbally transmitted record of the teachings, deeds and sayings, silent permissions (or disapprovals) of Hazrat Mohammad, as well as reported by his companions.
There are three types of sunnah: 1.Sunnah Qawliyyah: the sayings of Muhammad, generally synonymous with hadith (the sayings of Mohammad as noted down by his companions) 2. Sunnah Fiiliyyah: actions of Mohammad (both: religious and worldly actions) 3. Sunnah Taqririyyah: the approvals of Mohammad regarding the actions of the companions (which occurred in two ways: when Muhammad kept silent for an action and did not oppose it OR when Mohammad showed his pleasure and smiled for a companion’s action).
Islamic ceremony of circumcision too is known as Sunnat. (It is called’ sunnat’ because it was done by Mohammed himself, i.e. in the tradition of Mohammed.