cathode n 1: a negatively charged electrode that is the source of electrons entering an electrical device [ant: {anode}] 2: the positively charged terminal of a voltaic cell or storage battery that supplies current [ant: {anode}]
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]