cathode

[ kath-ohd ]

Phonetic (Standard)IPA

noun

the electrode or terminal by which current leaves an electrolytic cell, voltaic cell, battery, etc.
the positive terminal of a voltaic cell or battery.
the negative terminal, electrode, or element of an electron tube or electrolytic cell.

cathode

/ kæˈθɒdɪk; -ˈθəʊ-; ˈkæθəʊd; kæˈθəʊdəl /

the negative electrode in an electrolytic cell; the electrode by which electrons enter a device from an external circuit
the negatively charged electron source in an electronic valve
the positive terminal of a primary cell

cathode

/ kăth′ōd′ /

The negative electrode in an electrolytic cell, toward which positively charged particles are attracted. The cathode has a negative charge because it is connected to the negatively charged end of an external power supply.
The source of electrons in an electrical device, such as a vacuum tube or diode.
The positive electrode of a voltaic cell, such as a battery. The cathode gets its positive charge from the chemical reaction that happens inside the battery, not from an external source.
Compare anode

Origin of cathode¹

1825–35; < Greek káthodos a way down, equivalent to kat- cat- ( def ) + hodós way

Origin of cathode¹

C19: from Greek kathodos a descent, from kata- down + hodos way

His discovery was in effect that electric rays emanated from the part of the tube struck by the cathode rays.

The plate where the current goes out, the cathode, C, increases in weight since some of the silver is deposited.

The diagram, of the tube shows that the main tube has been expanded round the edges of the cathode.

This is to reduce the heating consequent on the projection of cathode rays from the edges of the disc against the glass tube.

When the annealing is finished the side tube is bent as shown to serve as a handle when the time comes to mount the cathode.

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