\Per"sism\, n.
Ancient Persian religion, esp. as represented by the Magi.
      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.

\Per"sism\, n.
A Persian idiom.