α. Middle English rivyn, Middle English ryffen (northern), Middle English–1600s riuen, Middle English–1600s ryuen, Middle English–1600s ryven, 1600s rivin, 1600s riv'n, 1600s– riven; English regional (northern) 1800s– rivven, 1900s– reaven; Scottish pre-1700 riffin, pre-1700 riffyne, pre-1700 rifin, pre-1700 rifyn, pre-1700 riuen, pre-1700 rivin, pre-1700 riwen, pre-1700 ryvin, pre-1700 rywen, pre-1700 rywin, pre-1700 rywine, pre-1700 rywyn, pre-1700 1700s– riven, 1900s– rivvan (Orkney); N.E.D. (1909) also records a form Middle English riven.
β. late Middle English reuene, late Middle English–1500s reuen, late Middle English–1500s revyn, 1500s reven; Scottish pre-1700 reaven, pre-1700 reiffin, pre-1700 reiuen, pre-1700 reiven, pre-1700 reuen, pre-1700 reuin, pre-1700 revin, pre-1700 revyn, pre-1700 rewin, pre-1700 rewine, pre-1700 rewing, pre-1700 rewyn, pre-1700 rewyne, pre-1700 reyuen.