Source : Webster's Revised Unabridged Dictionary (1913)

Prognosis \Prog*no"sis\, n. [L., fr. Gr. ?, fr. ? to know
   beforehand; ? before + ? to know. See {Know}.] (Med.)
   The act or art of foretelling the course and termination of a
   disease; also, the outlook afforded by this act of judgment;
   as, the prognosis of hydrophobia is bad.

Source : WordNet®

prognosis
     n 1: a prediction about how something (as the weather) will
          develop [syn: {forecast}]
     2: a prediction of the course of a disease [syn: {prospect}, {medical
        prognosis}]
     [also: {prognoses} (pl)]