imperium vs dominance

imperium and dominance both are nouns.

Word	Noun	Adjective	Verb	Adverb
imperium	Yes	No	No	No
dominance	Yes	No	No	No

As nouns, dominance is a hypernym of imperium; that is, dominance is a word with a broader meaning than imperium:

Other hypernyms of imperium include authorisation, authority, authorization, potency, say-so.

imperium (noun)	dominance (noun)
supreme authority; absolute dominion	the power or right to give orders or make decisions
the domain ruled by an emperor or empress; the region over which imperial dominion is exercised	superior development of one side of the body
	the organic phenomenon in which one of a pair of alleles present in a genotype is expressed in the phenotype and the other allele of the pair is not
	the state that exists when one person or group has power over another