A priestess is a woman in a non-Christian religion who has particular duties and responsibilities in a place where people worship. see also high priestess. a woman with religious duties and responsibilities in some non-Christian religions
If you call a woman the high priestess of a particular thing, you are saying in a slightly mocking way that she is considered by people to be expert in that thing. the American high priestess of wit. The female head or chief proponent, as of a movement or doctrine: the high priestess of modern art