The Collaborative International Dictionary of English v.0.48:

Etherize \E"ther*ize\, v. t. [imp. & p. p. Etherized; p. pr. &
   vb. n. Etherizing.] [Cf. F. ['e]th['e]riser.]
   1. To convert into ether.
      [1913 Webster]

   2. To render insensible by means of ether, as by inhalation;
      as, to etherize a patient.
      [1913 Webster]

WordNet (r) 3.0 (2006):

etherize
    v 1: anesthetize with ether [syn: etherize, etherise]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "etherize":
   KO, aerate, aerify, anesthetize, atomize, bedaze, benumb, besot,
   blunt, carbonate, chlorinate, chloroform, coldcock, deaden,
   desensitize, distill, dope, drug, dull, emit, etherify, evaporate,
   exhale, fluidize, fractionate, freeze, fume, fumigate, gasify,
   give off, hydrogenate, kayo, knock out, knock senseless,
   knock stiff, knock unconscious, lay out, narcotize, numb, obtund,
   oxygenate, palsy, paralyze, perfume, put to sleep, reek, send out,
   smoke, spray, steam, stun, stupefy, sublimate, sublime, vaporize,
   volatilize