Is it farther or further?
late 14c., from Old French silogisme "a syllogism," from Latin syllogismus, from Greek syllogismos "a syllogism," originally "inference, conclusion, computation, calculation," from syllogizesthai "bring together, premise, conclude," literally "think together," from syn- "together" (see syn-) + logizesthai "to reason, count," from logos "a reckoning, reason" (see logos).
For example, every virtue is laudable; kindness is a virtue; therefore kindness is laudable.
Strangely, a syllogism can still be true if the premises are false. Compare inference rule.
[Relationship between premises?]