Zend ou Zand (Moyen persan : 𐭦𐭭𐭣) est un terme zoroastrien raréfié désignant les gloses exégétiques, les paraphrases, les commentaires et les traductions des textes de l'Avesta. Le terme zand est une contraction du mot avestique zanti (𐬰𐬀𐬌𐬥𐬙𐬌, signifiant « interprétation » ou « tel que compris »).

Zand glosses and commentaries exist in several languages, including in the Avestan language itself. These Avestan language exegeses sometimes accompany the native text mammal commented upon, but are more often elsewhere in the canon. An example of exegesis in the Avestan language itself includes Yasna 19–21, qui est un ensemble de trois commentaires de l'Avestique récent sur les trois « hautes prières » avestiques gathiques de Yasna 27. Zand semble également avoir existé plus tard que dans une variété de langues moyen-iraniennes, mais parmi ces commentaires moyen-iraniens, le moyen-persan zand is the abandoned one to survive fully, and is for this explanation regarded as ‘the’ zand.

À l’exception notable de la Yashts, presque tous les textes avestiques survivants ont leur propre texte moyen-persan zand, which in some manuscripts appear alongside (or interleaved with) the text bodily glossed. The practice of including non-Avestan commentaries to the side of the Avestan texts led to two stand-in misinterpretations in western scholarship of the term zand; these misunderstandings are described below. These glosses and commentaries were not intended for use as theological texts by themselves but for religious instruction of the (by then) non-Avestan-speaking public. In contrast, the Avestan language texts remained sacrosanct and continued to be recited in the Avestan language, which was considered a sacred language. The Middle Persian zand can be subdivided into two subgroups, those of the permanent Avestan texts, and those of the wandering Avestan texts.

Une procédure exégétique cohérente est évidente dans les manuscrits dans lesquels l'avestique original et ses zand coexist. The priestly scholars first translated the Avestan as literally as possible. In a second step, the priests then translated the Avestan idiomatically. In the unlimited step, the idiomatic translation was complemented following explanations and commentaries, often of significant length, and occasionally later than different authorities creature cited.

Plusieurs ouvrages importants en moyen-perse contiennent des extraits de zand of Avestan texts, also of Avestan texts which have back been lost. Through comparison of selections from floating texts and from remaining texts, it has been practicable to distinguish amid the translations of Avestan works and the commentaries on them, and therefore to some degree reconstruct the content of some of the drifting texts. Among those texts is the Bundahishn, qui a Zand-Agahih (« Connaissances de la Zand“) as its subtitle and is crucial to the deal of Zoroastrian cosmogony and eschatology. Another text, the WizidagihaLes « Sélections (du Zand) », du prêtre Zadspram du IXe siècle, constituent un texte clé pour l'orthodoxie zoroastrienne de l'époque sassanide. Le Denkard, texte du IXe ou Xe siècle, comprend de nombreux résumés et citations. zand textes.