Mid 17th century; earliest use found in Ephraim Pagitt (1574–1646), heresiologist. Either from post-classical Latin Socinismus, or independently from the surname of Laelius and Faustus Socinius + -ism.
Definition of Socinism in US English:
Socinism
nounˈsəʊsɪnɪz(ə)m
rare
= Socinianism.
Origin
Mid 17th century; earliest use found in Ephraim Pagitt (1574–1646), heresiologist. Either from post-classical Latin Socinismus, or independently from the surname of Laelius and Faustus Socinius + -ism.