In Judaism, Nusach (Hebrew: נוסח, romanized: nusaḥ, Modern Hebrew pronunciation nusakh,[1] plural (נוסחים nusaḥim, also Yiddish: נוסחאות, romanized: nuskhóes)) is the exact text of a prayer service; sometimes the English word "rite" is used to refer to the same thing.
In common use, nusach has come to signify the entire liturgical tradition of the community, including the musical rendition.
Nusach Ashkenaz is the style of service conducted by Ashkenazi Jews, originating from central and eastern Europe.
Nusach Sefard is the style of service used by some Jews of central and eastern European origins, especially Hasidim, who adopted some Sephardic customs emulating the practice of the Ari's circle of kabbalists, most of whom lived in the Land of Israel.
Textually speaking it is based in a large part on the Sephardic rite, but in melody, feel and pronunciation it is overwhelmingly Ashkenazi.
Nusach Ari means, in a general sense, any prayer rite following the usages of Rabbi Isaac Luria, the AriZal, in the 16th century.
One form of it is used by the Dor Daim, who attempt to safeguard the older Baladi tradition of Yemenite Jewish observance.
[citation needed] Rabbi David Bar-Hayim disputes this and permits a Jew to change his nusach at any time, even on a daily basis.