death knell vs prognostication

death knell and prognostication both are nouns.

Word	Noun	Adjective	Verb	Adverb
death knell	Yes	No	No	No
prognostication	Yes	No	No	No

As nouns, prognostication is a hypernym of death knell; that is, prognostication is a word with a broader meaning than death knell:

Other hypernyms of death knell include omen, portent, presage, prodigy, prognostic.

death knell (noun)	prognostication (noun)
a bell rung to announce a death	knowledge of the future (usually said to be obtained from a divine source)
an omen of death or destruction	a statement made about the future
	a sign of something about to happen