从语言上讲，“Sunnah”（逊奈）意为“方法”。但在伊斯兰教法（Shari'ah）中，它指的是从先知ﷺ那里传述下来的、属于“奈菲来”（nafilah）的功修，例如推荐性的拜功（即逊奈拜，rakaat as-Sunnah），这些与“法尔德”（fard，即必行的功课）有所区别。不应理解为：某一行为之所以称为逊奈，是因为它来自先知ﷺ，而法尔德则来自安拉（SWT）。逊奈与法尔德都来自安拉（SWT）；而拉苏勒·安拉ﷺ只是安拉（SWT）的传达者，因为拉苏勒·安拉ﷺ所说的话并非出于私欲，而只是安拉（SWT）启示给他的，即“瓦希”（wahy）。因此，尽管逊奈是从先知ﷺ那里传述下来的，但它是作为推荐性的行为即“奈菲来”而被传述的，所以才被称为逊奈；正如法尔德是作为必行的行为而被传述的一样。 由此，晨礼（fajr）的两拜必行拜功，是通过确凿的传述（即“泰瓦图尔”，tawatur）从先知ﷺ那里传下来的，属于法尔德；晨礼的两拜推荐拜功，也同样通过确凿的传述（泰瓦图尔）作为逊奈（奈菲来）而传下来。两者都来自安拉（SWT），而非来自拉苏勒·安拉ﷺ本人。因此，在功修（‘ibadat）的行为中，命令（amr）要么是法尔德，要么是奈菲来；在其他行为中，则是法尔德、曼杜卜（mandoob）或穆巴赫（mubaH）。换言之，奈菲来与曼杜卜是相同的，只是称呼不同：一个被称为奈菲来，一个被称为逊奈。

Linguistically Sunnah means the method. However, in terms of the Shari’ah it designates the nafilah that has been narrated from the Prophet (saw) such as the recommended rakaat (rakaat as-Sunnah) which are distinct from fard (compulsory). It should not be understood that the action is called Sunnah because it is from the Prophet and that the fard is from Allah (swt). The Sunnah and the fard are both from Allah (swt); and Rasool Allah (saw) is but a conveyor from Allah (swt), because the Rasool Allah (saw) uttered not out of whims but only that which was revealed to him from Allah (swt) i.e. wahy. Thus, although Sunnah is narrated from the Prophet (saw), nevertheless it is narrated as a recommended action i.e. nafilah that is why it is called sunnah; in the same way that the fard has been narrated as a compulsory action. Hence, the two compulsory raka'at of the dawn (fajr) prayer have been narrated from the Prophet (saw) through decisive reports, known as tawatur, as being fard; and the two recommended raka'at of the fajr prayer have also been narrated through decisive reports (tawatur) as being Sunnah (nafilah); and both are from Allah (swt) and not from Rasool Allah (saw) himself. Thus the command (amr) is either fard or nafilah in actions of worship (‘ibadat), and fard , mandoob or mubaH in other actions. In other words, nafilah is the same as mandoob, but it is called nafilah, and called as Sunnah.

Sunnah 一词还指除《古兰经》之外，所有源自安拉的使者（愿安拉赐福并使其平安）的沙里尔证据。这包括他的言语、行为以及默许（即他对于在其面前所做之事的沉默）。

The Sunnah also means all the shar’ai evidences which came from Rasool Allah (saw) other than the Qur'an. This includes his speech, actions and consent (his silence upon actions performed before him).