A Rebbe (Yiddish: רבי, romanized: rebe) or Admor (Hebrew: אדמו״ר) is the spiritual leader in the Hasidic movement, and the personalities[clarification needed] of its dynasties.
[1] The titles of Rebbe and Admor, which used to be a general honorific even before the beginning of the movement, became, over time, almost exclusively identified with its Tzadikim.
A significant function of a rav is to answer questions of halakha (the corpus of Jewish law), but he is not as authoritative as a posek.
The short form reb is an honorific for Orthodox Jewish men, who are most likely to have profound knowledge of the Talmud and Torah, as opposed to Reconstructionist, Reform or Conservative Judaism.
Hasidim use the term rebbe also in a more elevated manner, to denote someone that they perceive not only as the religious leader or nasi[4] of their congregation, but as their spiritual adviser and mentor.
Hasidim use the concept of a (non-Hasidic) rebbe in the simple sense of rabbi, as the Yiddish-German equivalent to the Hebrew word רַבִּי rabi [ˈʁäbi].
The practice became widespread in America in the early 1900s when Hasidic rebbes began to emigrate to the United States and was derived from the German Grossrabbiner.
These righteous people's perception (of both spiritual and physical, not to mention temporal matters) transcends the apparent boundaries of existence.
In some movements the Hasidim believe that their rebbe is the "tzadik hador" (tzaddik of the generation) and would regard any thought that detracts from his perfection and holiness as heresy.
[1] based on traditional Kabbalistic concepts and terminology, Hasidic philosophy bridged deveikut, a Jewish concept referring to closeness to God, to the Hasidic rebbe, embodying and channeling the Divine flow of blessing to the world, because Creation is dependent on the continuous flow of Divine lifeforce, without which it would revert to nothingness.
For example, Rabbi Aaron Roth (Reb Areleh, as he was called) the first rebbe of Shomer Emunim, told his Hasidim to pause frequently while eating their meals to keep them from overindulging.
These include the leading of prayer on Shabbat and Holy Days, performing mitzvot with their Hasidim, and participating in or officiating at weddings, brit milahs, and other events.
Hasidic rebbes also play a central role in the intellectual and social life of their communities, delivering sermons and dialogues and building educational and religious institutions.