*persism*

n. An ancient Persian religion, esp. as represented by the Magi; a form of Zoroastrianism. [ 1913 Webster + PJC ]

This system we shall call 'Persism', in order to free ourselves of the popular associations still connected with such terms as magism, Parseeism, and so forth; meaning by 'Persism' the teaching of Zarathustra as it affected the Greek and Latin world. E. Vernon Arnold. [ Webster 1913 Suppl. ]