In Judaism, a rabbi is a teacher of Torah. This title derives from the Hebrew word , meaning "My Master" (irregular plural רבנים ), which is the way a student would address a master of Torah. The word "master" רב literally means "great one".
Rav (Heb. ) is the Hebrew word for rabbi. For a more nuanced discussion see semicha. The term is also frequently used by Orthodox Jews to refer to one's own rabbi.