[proh-sil-uh-jiz-uh m]
noun Logic.
  1. 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.
Compare episyllogism.

Origin of prosyllogism

1575–85; < Medieval Latin prosyllogismus < Greek prosyllogismós. See pro-2, syllogism Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018