Where does “рёв” come from?

рёв (Russian) comes from Ukrainian ревіти, from Old East Slavic рюти, from Proto-Slavic řuti, from Proto-Indo-European rew- — to roar, growl, grumble; to roar; growl; grumble;...

рёв (Russian): roar, bellow; howl; genitive/accusative plural of...