Catchment

A geographical area draining to a sewer or receiving water.

Categorization

A structured process of placing items into sets according to related characteristics for prioritization.

Cathode

The electrode of an electrolytic cell at which reduction is the principal reaction (Electrons flow toward the cathode in the external circuit ). Typical cathodic processes are cations taking up electron and being discharged, oxygen being reduced, and the reduction of an element or group of elements from a higher to a lower valence state.

Cathodic

A process by which the corrosion of a metal pipeline may be protected by the use of an electrical current.

Cathodic Corrosion

An unusual condition (especially with Al, Zn, Pb) in which corrosion is accelerated at the cathode because the cathodic reaction creates an alkaline condition which is corrosive to certain metals.