According to the prevalent theory, the name Rus', like the Proto-Finnic name for Sweden (*rootsi), is derived from an Old Norse term for 'men who row' (rods-) because rowing was the main method of navigating the rivers of Eastern Europe, and could be linked to the Swedish coastal area of Roslagen (Rus-law) or Roden, as it was known in earlier times.[22][23] The name Rus' would then have the same origin as the Finnish and Estonian names for Sweden: Ruotsi and Rootsi.[23][24]
The term Kievan Rus' (Russian: Киевская Русь, romanized: Kiyevskaya Rus) was coined in the 19th century in Russian historiography to refer to the period when the centre was in Kiev.[25] In the 19th century it also appeared in Ukrainian: Київська Русь, romanized: Kyivska Rus.[26] In English, the term was introduced in the early 20th century, when it was found in the 1913 English translation of Vasily Klyuchevsky's A History of Russia,[27] to distinguish the early polity from successor states, which were also named Rus. The variant Kyivan Rus' appeared in English-language scholarship by the 1950s.[28] Later, the Russian term was rendered into Belarusian: Кіеўская Русь, romanized: Kiyewskaya Rus’ or Kijeŭskaja Ruś and Rusyn: Київска Русь, romanized: Kyïvska Rus′.
https://en.wikipedia.org/wiki/Kievan_Rus%27