An Etymological Dictionary of the German Language/Strom
Strom, m., ‘stream, torrent, current,’ from the equiv. MidHG. strôm (stroum), OHG. stroum; common to Teut. in the form straumo-. Comp. OSax. strôm, Du. stroom, AS. streám, E. stream, and the equiv. OIc. straumr. Teut. straumo- for srou-mo- is based on the Aryan root srū̆ (srou), ‘to flow,’ which appears in Gr. ῥέω (for *σρέϝω; ῥύσις, ‘flowing,’ for sru-ti-s), Sans. root sru, ‘to flow,’ OIr. sruth, ‘river,’ and sruaim (base sroumen), ‘stream.’ For the evolution of Aryan sr to str see Schwester and Strick.