A term used mostly by the African AmericanChristian religion. Meaning Woman. Of. God. Mainly used when addressing a female pastor, evangelist or a woman who clearly has a close relationship or walk with Christ.
Originally British usage was only meant when describing any dark skinned person either of African or Indo-Asian descent. It was more along the lines of the "negro" and such. THe modern Australian usage differs considerably as to include the Meditteranean races, including the non-European Turkish, Lebanese and Israeli Jews.