Theology is a term first used by Plato in The Republic (book ii, chap 18). The term is compounded from two Greek words theos (god) and logos (rational utterance). It has been defined as reasoned discourse about God or the gods, or more generally about religion or spirituality.
Christian theology is discourse concerning Christian faith. Christian theologians use rational analysis and argument to understand, explain, test, critique, defend or promote Christianity. Theology might be undertaken to help the theologian understand Christianity more truly,[1] make comparisons between Christianity and other traditions,[2] defend Christianity against critics, facilitate Christianity's reform,[3] assist in the propagation of Christianity,[4] draw on the resources of the Christian tradition to address some present situation or need,[5] or for a variety of other reasons.