1. The study of religion, especially the Christian faith and God’s relation to the world.
2. A religious theory, school of thought, or system of belief.
3. A course of specialized religious training, especially one intended to lead students to a vocation in the Christian Church.
4. A system of religious knowledge or beliefs.

1. The search for the place, or places, in the brain where religious beliefs originate: "Neurotheology mixes terms and methods from science and religion in an attempt to confer the authority of science upon religion."

"In neurotheology, psychologists and neurologists try to determine which regions turn on, and which areas turn off, during experiences that seem to exist outside time and space."

2. The scientific study of religious or spiritual feelings by using the tools of psychology and neuroscience to probe the neural basis of religious experience: "Neurotheology is said to be a passion for uncovering the neurological evidence of spiritual and mystical experiences; for discovering, in short, what happens in people's brains when they sense that they "have encountered a reality different from—and, in some crucial sense, higher than—the reality of everyday experiences."

"Research in this field of neurotheology roughly divides into two types: (1) either stimulating spiritual experience with drugs, or (2) studying brain activity during such experiences using imaging techniques to see which regions of the brain are changing; and for some researchers, 'these moments of calm or absence of mental stress are little more than common deviations or variations in brain chemistry'."