prognostication n.

1650s, "forecast of the probable course and termination of a case of a disease," from Late Latin prognosis, from Greek prognōsis "foreknowledge," also, in medicine, "predicted course of a disease," from stem of progignōskein "come to know beforehand," from pro- "before" (see pro-) + gignōskein "come to know" (from PIE root *gno- "to know").

An earlier form in the same sense was pronostike (early 15c.), from Medieval Latin pronosticum. The general (non-medical) sense of "a forecast of the course of events" in English is from 1706. A back-formed verb prognose is attested from 1837; the earlier verb was Middle English pronostiken (c. 1400), from Medieval Latin pronosticare.  Related: Prognosed; prognosing.

"foretell by means of present signs," early 15c., prenosticaten, a back-formation from prognostication and also from Medieval Latin prognosticatus, past participle of prognosticare"foretell," from Latin prognostica "sign to forecast weather," from neuter plural of Greek prognōstikos "foreknowing," from progignōskein (see prognosis). Related: Prognosticated; prognosticating.