O.E. wanian "make or become smaller gradually," from P.Gmc. *wanojanan (cf. O.S. wanon, O.N. vana, O.Fris. wania, M.Du. waenen, O.H.G. wanon "to wane, to grow less"), from *wano- "lacking," from PIE *we-no-, from base *eue- "to leave, abandon, give out" (see vain). Related: waned, wanes.
