Asman is the Avestan

Avestan language

Avestan is an East Iranian language known only from its use as the language of Zoroastrian scripture, i.e. the Avesta, from which it derives its name...

 and Middle Persian

Middle Persian

Middle Persian , indigenously known as "Pârsig" sometimes referred to as Pahlavi or Pehlevi, is the Middle Iranian language/ethnolect of Southwestern Iran that during Sassanid times became a prestige dialect and so came to be spoken in other regions as well. Middle Persian is classified as a...

 name of the Zoroastrian

Zoroastrianism

Zoroastrianism is a religion and philosophy based on the teachings of prophet Zoroaster and was formerly among the world's largest religions. It was probably founded some time before the 6th century BCE in Greater Iran.In Zoroastrianism, the Creator Ahura Mazda is all good, and no evil...

 divinity that is the hypostasis of the sky. Asman is the "highest heaven," and is distinguished from the firmament (thwasha), which lies nearer the earth. The 27th day of the Zoroastrian calendar

Zoroastrian calendar

This article treats of the reckoning of days, months and years in the calendar used by adherents of the Zoroastrian faith. Zoroastrian religious festivals are discussed elsewhere, but have a fixed relationship to Nawruz, the New Year festival, whose timing is discussed below...

 is dedicated to him.

In the Avesta

Avesta

The Avesta is the primary collection of sacred texts of Zoroastrianism, composed in the Avestan language.-Early transmission:The texts of the Avesta — which are all in the Avestan language — were composed over the course of several hundred years. The most important portion, the Gathas,...

, specifically in the Vendidad

Vendidad

The Vendidad or Videvdat is a collection of texts within the greater compendium of the Avesta. However, unlike the other texts of the Avesta, the Vendidad is an ecclesiastical code, not a liturgical manual.-Name:...

, the word is mentioned as being the first thing created. The word is also the origination of the word asman in modern Persian

Persian language

Persian is an Iranian language within the Indo-Iranian branch of the Indo-European languages. It is primarily spoken in Iran, Afghanistan, Tajikistan and countries which historically came under Persian influence...

 and Pashto

Pashto language

Pashto , known as Afghani in Persian and Pathani in Punjabi , is the native language of the indigenous Pashtun people or Afghan people who are found primarily between an area south of the Amu Darya in Afghanistan and...

.