Definition: The word "MRTG" is not commonly found in the Bible, but it may be a reference to a term or concept from religious or spiritual beliefs. Definition of "MRTG": Meaning "Mystery-Riddle," "Riddle-Mystery." It typically refers to a concept or idea that is perplexing or mysterious. In Christianity, for example, it can refer to the mystery of the Trinity (God as Father, Son, and Holy Spirit). Keep it short, concise, and in English!