Dictionary.net

• First two propositions of a syllogism from which the conclusion or inference is drawn.

1874 - Etymological and pronouncing dictionary of the English language
By Stormonth, James, Phelp, P. H.

• [L.] (Log.) The two propositions or antecedents in a Syllogism, from which the conclusion or consequence follows.

1895 - Glossary of terms and phrases
By Henry Percy Smith