These norsemen were known "by the ethnonym Rus (pronounced "Roos"). The origin of this term is obscure, and though some claim it stems from the West Finnic name for Sweden, Ruotsi, there is little agreement." (from article)
But "according to the most prevalent theory, the name 'Rus', like the Proto-Finnic name for Sweden (Ruotsi), is derived from an Old Norse term for "the men who row". (from https://en.wikipedia.org/wiki/Rus%27_people)
The ethonym is traceable in names such the eastern Swedish district of Roslagen (from where a lot of these norsemen presumably set sail), as well as 'Rus'sia.
But "according to the most prevalent theory, the name 'Rus', like the Proto-Finnic name for Sweden (Ruotsi), is derived from an Old Norse term for "the men who row". (from https://en.wikipedia.org/wiki/Rus%27_people)
The ethonym is traceable in names such the eastern Swedish district of Roslagen (from where a lot of these norsemen presumably set sail), as well as 'Rus'sia.