Kievan Rus' vs Rus

Kievan Rus' and Rus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Kievan Rus'	Yes	No	No	No
Rus	Yes	No	No	No

As nouns, Kievan Rus' and Rus are synonyms defined as:

Kievan Rus' and Rus: the medieval Russian state established by Scandinavian traders in the 9th century; the capital was first in Novgorod and then in Kiev

Kievan Rus' (noun)	Rus (noun)
the medieval Russian state established by Scandinavian traders in the 9th century; the capital was first in Novgorod and then in Kiev	the medieval Russian state established by Scandinavian traders in the 9th century; the capital was first in Novgorod and then in Kiev