'Syllogism' is Greek for 'reckoning together' — Aristotle's name for deductive argument structure.
A form of deductive reasoning consisting of two premises and a conclusion, in which the conclusion necessarily follows from the premises; the fundamental unit of Aristotelian logic.
From Old French 'silogisme,' from Latin 'syllogismus,' from Greek 'syllogismos' (συλλογισμός), meaning a reckoning together or inference. Derives from 'syllogizesthai' (to reckon together, conclude by reasoning), composed of 'syn-' (together, with) + 'logizesthai' (to reckon, calculate), from 'logos' (word, reason, account, proportion), itself from PIE *leǵ- (to gather, collect, choose). Aristotle formalized the syllogism in his Organon as the backbone of deductive logic: a three-part argument where a conclusion follows
The most famous syllogism in history — 'All men are mortal; Socrates is a man; therefore, Socrates is mortal' — was not actually used by Aristotle. It became the standard textbook example only in medieval and early modern logic. Aristotle's own examples were more abstract, using letters