The Zoroastrian name of the religion is Mazdayasna, which combines Mazda- with the Avestan language word yasna, meaning "worship, devotion".
Post-Zoroastrian scripture introduced the concept of Ahriman, the Devil, which was effectively a personification of Angra Mainyu.
Zoroastrianism has no major theological divisions, though it is not uniform; modern-era influences having a significant impact on individual and local beliefs, practices, values and vocabulary, sometimes merging with tradition and in other cases displacing it.
The resulting conflict involves the entire universe, including humanity, which has an active role to play in the conflict.
In Zoroastrian tradition, the "chaotic" is represented by Angra Mainyu (also referred to as "Ahriman"), the "Destructive Principle", while the benevolent is represented through Ahura Mazda's Spenta Mainyu, the instrument or "Bounteous Principle" of the act of creation.
The most important texts of the religion are those of the Avesta, which includes the writings of Zoroaster known as the Gathas, enigmatic poems that define the religion's precepts, and the Yasna, the scripture.
The full name by which Zoroaster addressed the deity is: Ahura, The Lord Creator, and Mazda, Supremely Wise.
In older English sources, the terms Gheber and Gueber (both deriving from Persian for infidel, compare giaour) were used to refer to Zoroastrians; however, these terms are considered offensive and have fallen out of use.
Zoroastrian philosophy is identified as having been known to Italian Renaissance Europe through an image of Zoroaster in Raphael's "School of Athens" by Giorgio Vasari in 1550.
The first surviving reference to Zoroaster in English scholarship is attributed to Thomas Browne (1605–1682), who briefly refers to the prophet in his 1643 Religio Medici, followed by the Oxford English Dictionary's record of the 1743 (Warburton, Pope's Essay).