Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† syllŏgismus or -os (syllogismus, Sid. Pan. 205), i, m., = συλλογισμός, a form of reasoning in which a conclusion is drawn from two premises, a syllogism (post-Aug.), Gell. 2, 8, 7; Sen. Ep. 108, 12; 113, 26; Plin. Ep. 2, 3, 3; Quint. 3, 6, 43; 3, 6, 77; 3, 6, 88; 3, 6, 103; 5, 10, 88; 5, 14, 14 al.