cathode

n. negatively-charged electrode, negative pole of a current (Electricity)

A cathode is an electrode through which (positive) electric current flows out of a polarized electrical device. Mnemonic: CCD (Cathode Current Departs). To dispel a common misconception, often incorrectly inferred from the correct fact that in all electrochemical devices positively charged cations move towards the cathode and/or negatively charged anions move away from it, cathode polarity is not always negative but depends on the device type, and sometimes even in which mode it operates, as determined by the above current direction based universal definition. Examples:In a discharging battery or galvanic cell (drawing) the cathode is the positive terminal, where conventional current flows out. This outwards current is carried internally by positive ions moving from the electrolyte to the positive cathode (chemical energy is responsible for this "uphill" motion). It is continued externally by electrons moving inwards, negative charge moving one way amounting to positive current flowing the other way.In a recharging battery, or an electrolytic cell, the cathode is the negative terminal, which sends current back to the external generator.In a diode, it is the negative terminal at the pointed end of the arrow symbol, where current flows out of the device. Note electrode naming for diodes is always based on the direction of the forward current (that of the arrow, in which the current flows "most easily"), even for types such as zener diodes or solar cells where the current of interest is the reverse current.In a cathode ray tube, it is the negative terminal where electrons flow in, i.e. where current flows out of the device.
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Noun
1. a negatively charged electrode that is the source of electrons in an electrical device
(antonym) anode
(hypernym) electrode
(hyponym) photocathode
(part-holonym) electrolytic cell
2. the positively charged terminal of a voltaic cell or storage battery that supplies current
(antonym) anode
(hypernym) terminal, terminus, depot
(part-holonym) storage battery, accumulator

n. cathode

(n.)
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.