whale n.

Old English walu "ridge, bank" of earth or stone, later "ridge made on flesh by a lash" (related to weal (n.2)); from Proto-Germanic *walu- (source also of Low German wale "weal," Old Frisian walu "rod," Old Norse völr "round piece of wood," Gothic walus "a staff, stick," Dutch wortel, German wurzel "root"), from PIE root *wel- (3) "to turn, revolve." The common notion perhaps is "raised line." Used in reference to the ridges of textile fabric from 1580s. Wales "horizontal planks which extend along a ship's sides" is attested from late 13c.

"sea-unicorn, dolphin-like Arctic sea mammal" (one of the teeth of the male is enormously developed into a straight spirally fluted tusk), 1650s, from Danish and Norwegian narhval, probably a metathesis of Old Norse nahvalr, literally "corpse-whale," from na "corpse" (see need (n.)) + hvalr "whale" (see whale). If this is right, it likely was so called from its whitish color, resembling that of dead bodies. But according to nature writer Barry Lopez ("Arctic Dreams"), Winfred P. Lehmann, professor of Germanic linguistics, suggested the name was folk-etymology and said nahvalr was a West Norse term meaning "whale distinguished by a long, narrow projection."