Old English rice "strong, powerful; great, mighty; of high rank," in later Old English "wealthy," from Proto-Germanic rikijaz (source also of Old Norse rikr, Swedish rik, Danish rig, Old Frisian rike "wealthy, mighty," Dutch rijk, Old High German rihhi "ruler, powerful, rich," German reich "rich," Gothic reiks "ruler, powerful, rich"), borrowed from a Celtic source akin to Gaulish rix, Old Irish ri (genitive rig) "king," from PIE root *reg- "move in a straight line," with derivatives meaning "to direct in a straight line," thus "to lead, rule" (compare rex).
