A chemical reaction, which employs a catalyst. A catalyst is a substance that aids a reaction but remains unchanged. Examples of catalytic reactions include catalytic converters in automobiles that use platinum to reduce pollution emissions and boat resins, which are hardened (or cured) using a catalyst.
Catch
Automatically securing latch on a gate or door.
Catch basin
Basin which collects water that has been rerouted from another location.
Catenary
When a line is freely suspended from two fixed points, the curve that occurs in the cable is a catenary.
Cathedral ceiling
High, vaulted, open ceiling.
Cathode
The negative pole or electrode of an electrolytic cell, vacuum tube, etc., where electrons enter (current leaves) the system; the opposite of an anode.
Cathode disconnect ballast
An electromagnetic ballast that disconnects a lamp's electrode heating circuit once is has started; often called "low frequency electronic" ballasts.
Cathode ray tube (crt)
Monitor screen of a computer.
Cathodic
Metals low in the Galvanic Series.
Cathodic protection
A method of preventing oxidation of the exposed metal in structures by imposing between the structure and the ground a small electrical voltage.
