Rebbe
Rebbe may refer to the leader of a Hasidic Judaism movement, a person's main rosh yeshiva (a rabbi who is the academic head of a school) or mentor, or to an elementary school teacher as referred to by his/her students.
In many Hasidic groups the Rebbe gives spiritual guidance; but for questions of halakhah they ask a Rav. This Rav is sometimes referred to as the Rav of the Hasidic group. This position normally is occupied by the Av Beis Din or chief justice, of a Hasidic group. In some Hasidic groups, such as Belz and Satmar, the Rebbe and Rav are concurrent positions. In Hasidic groups with similar organizations, the Admo"r will be referred to by the interchangeable titles. In those groups where the positions are divided, they will not. For example, the Satmar Rav and the Satmar Rebbe are the same person. The Breslover Rebbe and the Breslover Rav are not.
Read more about this topic: Honorifics In Judaism