Meaning: The holy name of God in Hebrew which should not be spoken in vain.
Usage: Any four-letter profane word not to be spoken aloud.
From the Greek, "Tetragrammaton", meaning "four-letter word"
Exodus 6:3 And I appeared unto Abraham, unto Isaac, and unto Jacob, by the name of God Almighty, but by my name JEHOVAH was I not known to them.