Why is the ninth month called September?
1650s, "forecast of the probable course of a disease," from Late Latin prognosis, from Greek prognosis "foreknowledge," also, in medicine, "predicted course of a disease," from stem of progignoskein "come to know beforehand," from pro- "before" (see pro-) + gignoskein "come to know" (see gnostic). General (non-medical) use in English from 1706. A back-formed verb prognose is attested from 1837. Related: Prognosed; prognosing.
prognosis prog·no·sis (prŏg-nō'sĭs)
n. pl. prog·no·ses (-sēz)
A prediction of the probable course and outcome of a disease.
The likelihood of recovery from a disease.
A medical prediction of the future course of a disease and the chance for recovery.
Note: Prognosis is often used as a general term for predicting the unfolding of events: “The governor said that the prognosis for the state's financial future is bleak.”