Mid 16th century (in an earlier sense). From Osiandr-, stem of Osiander, Latinized form of the name of Andreas Hosemann, German Protestant theologian + -ian.
Definition of Osiandrian in US English:
Osiandrian
adjectiveˌɒsɪˈandrɪən
historical
Of or relating to Osiander or his beliefs.
Origin
Mid 16th century (in an earlier sense). From Osiandr-, stem of Osiander, Latinized form of the name of Andreas Hosemann, German Protestant theologian + -ian.