Old English walhnutu "nut of the walnut tree," literally "foreign nut," from wealh "foreign" (see Welsh) + hnutu (see nut). Compare Old Norse valhnot, Middle Low German walnut, Middle Dutch walnote, Dutch walnoot, German Walnuss. So called because it was introduced from Gaul and Italy, distinguishing it from the native hazel nut. Compare the Late Latin name for it, nux Gallica, literally "Gaulish nut." Applied to the tree itself from 1600 (earlier walnut tree, c. 1400).

"large pinniped carnivorous mammal" (the males are noted for their  enormous tusk-like canine teeth), 1650s, from Dutch walrus, which was probably a folk-etymology alteration (by influence of Dutch walvis "whale" and ros "horse") of a Scandinavian word, such as Old Norse rosmhvalr "walrus," hrosshvalr "a kind of whale," or rostungr "walrus." Old English had horschwæl, and later morse, from Lapp morsa or Finnish mursu, which ultimately might be the source, much garbled, of the first element in Old Norse rosmhvalr.