cath·ode 
(kăthōd′)
(kăthōd′)n. Abbr. ka
1. A negatively charged electrode, as of an electrolytic cell, storage battery, diode, or electron tube.
2. The positively charged terminal of a primary cell or a storage battery that is supplying current.
[Greek kathodos, descent : kat-, kata-, cata- + hodos, way, path.]
ca·thodic (kă-thŏdĭk) adj.
ca·thodi·cal·ly adv.