Jehovah

Jehovah is the conversion of the Hebrew (YHWH) to Latin. YHWH is the personal name of God in the Hebrew Bible, also known as the Old Testament to Christians.
The majority of scholars agree that the pronunciation of the Tetragrammaton is possibly—but most likely—Yahweh. The pronunciation of this name was simply lost because in Second Temple Judaism during the 3rd to 2nd centuries BCE, saying this name began to be discouraged because it was "too holy". So instead of saying YHWH, Jews used other ways to refer to their God, like "Adonai".