predominance vs ascendancy

predominance and ascendancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
predominance	Yes	No	No	No
ascendancy	Yes	No	No	No

As nouns, ascendancy is a hypernym of predominance; that is, ascendancy is a word with a broader meaning than predominance:

predominance: the state of being predominant over others
ascendancy: the state that exists when one person or group has power over another

Other hypernyms of predominance include ascendance, ascendence, ascendency, control, dominance.

predominance (noun)	ascendancy (noun)
the quality of being more noticeable than anything else	the state that exists when one person or group has power over another
the state of being predominant over others