syllogism n.

word-forming element meaning "together with, jointly; alike; at the same time," also sometimes completive or intensive, from Greek syn (prep.) "with, together with, along with, in the company of," from PIE *ksun- "with" (source also of Russian so- "with, together," from Old Russian su(n)-). Assimilated to -l-, reduced to sy- before -s- and -z-, and altered to sym- before -b-, -m- and -p-. Since 1970s also with a sense of "synthetic."

1580s, "the divine Word, second person of the Christian Trinity," from Greek logos "word, speech, statement, discourse," also "a computation, account," also "reason, judgment, understanding," from PIE *log-o-, suffixed form of root *leg- (1) "to collect, gather," with derivatives meaning "to speak," on notion of "to pick out words." The Greek word was used by Neo-Platonists in metaphysical and theological senses involving notions of both "reason" and "word" and subsequently picked up by New Testament writers.