preindication vs omen

preindication and omen both are nouns.

Word	Noun	Adjective	Verb	Adverb
preindication	Yes	No	No	No
omen	Yes	No	Yes	No

As nouns, omen is a hyponym of preindication; that is, omen is a word with a more specific, narrower meaning than preindication:

preindication: an event that is experienced as indicating important things to come
omen: a sign of something about to happen

Other hyponyms of preindication include war cloud, portent, presage, prodigy, prognostic, prognostication.

preindication (noun)	omen (noun)
an event that is experienced as indicating important things to come	a sign of something about to happen

preindication (verb)	omen (verb)
	indicate, as with a sign or an omen