In Judaism, a rabbiaɪ/ is a teacher of Torah. The basic form of the rabbi developed in the Pharisaic and Talmudic era, when learned teachers assembled to codify Judaism's written and oral laws. The first sage for whom the Mishnah uses the title of rabbi was Yohanan ben Zakkai, active in the early-to-mid first century CE. In more recent centuries, the duties of a rabbi became increasingly influenced by the duties of the Protestant Christian minister, hence the title "pulpit rabbis", and in 19th-century Germany and the United States rabbinic activities including sermons, pastoral counseling, and representing the community to the outside, all increased in importance.
The Hebrew word "master" רב rav[ˈʀäv], (irregular plural רבנים rabanim[ʀäbäˈnim]), which literally means "great one", is the original Hebrew form of the title. The form of the title in English and many other languages derives from the possessive form in Hebrew of rav: רַבִּי rabbi[ˈʀäbbi], meaning "My Master", which is the way a student would address a master of Torah.
The word 'Rav' in turn derives from the Semitic root ר-ב-ב (R-B-B), which in biblicalAramaic means "great" in many senses, including "revered", but appears primarily as a prefix in construct forms. Although the usage rabbim "many" (as 1 Kings 18:25, הָרַבִּים) "the majority, the multitude" occurs for the assembly of the community in the Dead Sea scrolls there is no evidence to support an association with the later title "Rabbi."
The root is cognate to Arabic ربّ rabb, meaning "lord" (generally used when talking about God, but also about temporal lords). As a sign of great respect, some great rabbis are simply called "The Rav".