higher rank vs seniority

higher rank and seniority both are nouns.

Word	Noun	Adjective	Verb	Adverb
higher rank	Yes	No	No	No
seniority	Yes	No	No	No

As nouns, higher rank and seniority are synonyms defined as:

higher rank and seniority: higher rank than that of others especially by reason of longer service

Other synonyms of higher rank include higher status, senior status.

higher rank (noun)	seniority (noun)
higher rank than that of others especially by reason of longer service	the property of being long-lived
	higher rank than that of others especially by reason of longer service