In addition,  Shia theology has two concepts that define religion as a whole. There are Roots of Religion (Usūl al-Dīn) and Branches of Religion (Furu al Din).
In addition, Shia theology contains two core elements that define religion comprehensively. These are the Foundations of Religion (Usūl al-Dīn) and the Outgrowths of Religion (Furu al-Din).