/ Dictionary / Index P prosyllogism: Meaning and Definition of Find definitions for: pro•syl•lo•gism Pronunciation: (prō-sil'u-jiz"um), [key] — n. Logic. a syllogism the conclusion of which is used as a premise of another syllogism; any of the syllogisms included in a polysyllogism except the last. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prosy prot- Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language