Br. Scot's quick definition: "Any talk about God, how God relates to the world and/or how the world relates to God."
"Have no other gods before Me." - God
"The mind is a factory for the creation of idols." - John Calvin
We all have gods, we can either choose the gods we follow, or we can just take whatever is on offer or whatever we happen upon. We can (and usually do) create whatever we want to be our god (proving Freud and Feuerbach right), live in fear of someone else's god (proving Nietzsche and Ayn Rand right), or we can seek the true God.
Theology exists all around us, "hidden" may be the wrong term, just floating around. Some of it is good, some is bad, some neutral. But few of us take the time to think about what we are absorbing and if it might in fact not be God, but something else posing as God.