Severn UK /ˈsɛv.ə(ɹ)n/US /ˈsɛv.ɚn/ noun3 •A river in England and Wales that flows into the Bristol Channel.There twice a day the Severn fills, The salt sea-water passes by, And hushes half the babbling Wye, And makes a silence in the hills. — 1850 •A long river in northern Ontario which flows into Hudson Bay. •A short river in central Ontario which flows into Lake Huron.