Rhine

From Middle English Rine, Ryne, from Old English Rīn (“the Rhine”), from Middle High German and Old High German Rīn, from Proto-West Germanic *Rīn, from Proto-Germanic *Rīnaz, from Gaulish Rēnos, from a Pre-Celtic or Proto-Celtic *reinos; one of a class of river names built from Proto-Indo-European *h₃reyH- (“to move, flow, run”).

Cognate with Old High German Rīn ("the Rhine"; > German Rhein), Old Norse Rín (“the Rhine”), Dutch Rijn (“the Rhine”). Related also to Latin rivus ("river"), in Celtic with an -n- suffix as in Old Irish rīan (“run”) (more at run).

The spelling with Rh- is due to the influence of Ancient Greek Ῥῆνος (Rhênos) (via French Rhin).