Entry 2 senses · 2 variants Webster, 1913 Socinian · So·cin·i·an · IPA /soʊˈsɪn.iː.ən/ a. n. 01 a. Of or pertaining to Socinus, or the Socinians. 1. Of or pertaining to Socinus, or the Socinians. 02 n. One of the followers of Socinus; a believer in Socinianism. 1. One of the followers of Socinus; a believer in Socinianism.