(1):

(a.) Indicating something future by signs or symptoms; foreshowing; aiding in prognosis; as, the prognostic symptoms of a disease; prognostic signs.

(2):

(a.) That which prognosticates; a sign by which a future event may be known or foretold; an indication; a sign or omen; hence, a foretelling; a prediction.

(3):

(a.) A sign or symptom indicating the course and termination of a disease.

(4):

(v. t.) To prognosticate.