The Collaborative International Dictionary of English v.0.48:

Cathode \Cath"ode\, n. [Gr. ? descent; ? down + ? way.]
   (Physics)
   The part of a voltaic battery by which the electric current
   leaves substances through which it passes, or the surface at
   which the electric current passes out of the electrolyte; the
   negative pole; -- opposed to anode. --Faraday.
   [1913 Webster]

   Cathode ray (Phys.), a kind of ray generated at the cathode
      in a vacuum tube, by the electrical discharge.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cathode ray
    n 1: a beam of electrons emitted by the cathode of an electrical
         discharge tube

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "cathode ray":
   Becquerel ray, Grenz ray, Roentgen ray, X radiation, X ray,
   actinic ray, alpha radiation, alpha ray, anode ray, beta radiation,
   beta ray, canal ray, cathode glow, collision emission,
   cosmic radiation, cosmic ray, cosmic ray bombardment,
   electron beam, electron emission, electron ray, field emission,
   gamma radiation, gamma ray, glow discharge, grid emission,
   infraroentgen ray, nuclear rays, photoemission, positive ray,
   radiorays, secondary emission, thermionic emission,
   thermionic grid emission