The term is derived from two Greek words meaning, respectively, "God" and "the study of" or "the knowledge of." It was used prior to the Christian era in Greek philosophy to mean the study of the gods. It became an important term in Christian usage in two senses. First, in the writings of the Greek Fathers it referred to that knowledge of God which human beings have through contemplation, mystical ascesis, and prayer, as opposed to the knowledge which we have through the created order. Second, in the western tradition during the medieval period of Scholasticism, it replaced the more common term "sacra doctrine," the study of scripture, as Christian thinkers became concerned with the rational, scientific analysis of Christian belief, especially with the kind of knowledge of God which derived from the study of the natural, created order. But theology never lost its deeper meaning of the knowledge of God derived from contemplation of the mystery of God which lies beyond all human knowing.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from "An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians," Don S. Armentrout and Robert Boak Slocum, editors.