Yasna

Yasna is the Avestan language name of Zoroastrianism`s principal act of worship, and also the name of the primary liturgical collection of Avesta texts, recited during that yasna ceremony. The function of the yasna ceremony is, very roughly described, to strengthen the orderly spiritual and material creations of Ahura Mazda against the assault of....
Found on http://en.wikipedia.org/wiki/Yasna

Yasna

(from the article `Iranian religion`) ...make images of their deities, nor did they build temples to house them, preferring to worship in the open. Worship of the gods was performed ... ...is a collection of songs or hymns, the Gths, thought to be in the main the very words of Zoroaster. They form a middle section of the chief ... .....
Found on http://www.britannica.com/eb/a-z/y/5

Yasna

(Av.) one of the books of the Avesta; the name of a high liturgical service in which the text of the Yasna is recited. (var. Yaçna, yazashna)
Found on http://www.avesta.org/zglos.html

Yasna

Zoroastrianism's principal act of worship, as well as the name of the primary liturgical collection of Avesta texts
Found on https://zoroastrianismforbeginners.weebly.com/glossary.html
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