dominance vs imperium

dominance and imperium both are nouns.

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

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

Other hyponyms of dominance include power of appointment, carte blanche, command, lordship, muscle, sovereignty.

dominance (noun)	imperium (noun)
the power or right to give orders or make decisions	supreme authority; absolute dominion
superior development of one side of the body	the domain ruled by an emperor or empress; the region over which imperial dominion is exercised
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