Are yams and sweet potatoes the same?
c.1200, from Old Norse vondr "rod, switch," (cf. Gothic wandus "rod," Middle Swedish vander), from Proto-Germanic *wend- "to turn," see wind (v.)). The notion is of a bending, flexible stick. Cf. cognate Old Norse veggr, Old English wag "wall," Old Saxon, Dutch wand, Old High German want, German Wand "wall," originally "wickerwork for making walls," or "wall made of wattle-work" (an insight into early Germanic domestic architecture). Magic wand is attested from c.1400 and shows the etymological sense of "suppleness" already had been lost.