Theology

Theology (from the Greek θεολογία, “theologia”, Θεός/Theos = “God” and λογία/logia = “sayings/oracle” and not from the suffixed λόγος/logos, “the study of”) isthe study of religion, religious belief and its underlying mechanisms, the history and philosophy of religion, divine revelation, and the divine and its nature.

Because I said so Theology was originally a branch of classical Western philosophy since Plato (who devided theoretical philosophy into mathematics, physics and theology¹⁾) and it remained so until relatively very recently when Kant pretty much disenfranchised it from philosophy; in Eastern philosophy, however, both remained rather tightly-knit. While now somewhat independent of it to no longer be entirely called a subset of Western philosophy, it's included here for the sake of keeping things tidy and perhaps a little bit intentionally convoluted. It's said that philosophy can't encompass theology because the latter relies too much into divine revelation to be assessed by reasoning, but this is an underestimation of a good chunk of the reason-based foundations of theology. Then again you could say that it's the philosophy of theology that is a subset of philosophy and not theology itself, though that would mean the compartmentalization of the constitutive elements of theology. Then again if philosophy is the rational processing of knowledge then a good argument can be built in favor of including theology, which is “thinking about religion” as a philosophical enterprise Because I said so.