Jihad

Literally "struggle" in Arabic, jihad has a range of definitions, starting with one not well known in the west. Its original basis was the struggle, within oneself, to follow the doctrine of submission to Allah; a translation of Muslim is "one who submits to God".

The concept broadened in the 12th century work of Ibn Tamiyya, who formulated an additional concept of "external" jihad, or struggle, usually but not necessarily armed, against enemies of Islam. Some theologians considered external jihad, when Islam faces enemies, to be an addition to the five basic Pillars of Islam.

Today, "armed" or "violent" jihad is a basic concept of jihadist terror groups such as al-Qaeda. It may be limited in scope to reestablishing Muslim rule (e.g., the Caliphate of Sunni Islam), or go beyond, into the interpretation of takfir, which calls for the killing of non-Muslims.