[ kath-ohd ]

  1. the electrode or terminal by which current leaves an electrolytic cell, voltaic cell, battery, etc.

  2. the positive terminal of a voltaic cell or battery.

  1. the negative terminal, electrode, or element of an electron tube or electrolytic cell.

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Origin of cathode

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

Words Nearby cathode Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use cathode in a sentence

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

    Invention | Bradley A. Fiske
  • The plate where the current goes out, the cathode, C, increases in weight since some of the silver is deposited.

    Physics | Willis Eugene Tower
  • The diagram, of the tube shows that the main tube has been expanded round the edges of the cathode.

    On Laboratory Arts | Richard Threlfall
  • This is to reduce the heating consequent on the projection of cathode rays from the edges of the disc against the glass tube.

    On Laboratory Arts | Richard Threlfall
  • 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.

    On Laboratory Arts | Richard Threlfall

British Dictionary definitions for cathode


/ (ˈkæθəʊd) /

  1. the negative electrode in an electrolytic cell; the electrode by which electrons enter a device from an external circuit

  2. the negatively charged electron source in an electronic valve

  1. the positive terminal of a primary cell

Origin of cathode

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

Derived forms of cathode

  • cathodal (kæˈθəʊdəl), cathodic (kæˈθɒdɪk, -ˈθəʊ-) or cathodical, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for cathode


[ kăthōd′ ]

  1. 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.

  2. The source of electrons in an electrical device, such as a vacuum tube or diode.

  1. 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.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.