1
: the electrode of an electrochemical cell at which reduction occurs:
a
: the negative terminal of an electrolytic cell
b
: the positive terminal of a galvanic cell
2
: the electron-emitting electrode of an electron tube
broadly : the negative electrode of a diode compare anode
cathodally adverb

Examples of cathode in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
However, the hydrogen-producing reaction at the cathode depends heavily on scarce platinum-group metals. — Atharva Gosavi, Interesting Engineering, 17 Oct. 2026 The deadline The first thing out of that loop is DRX, short for disordered rocksalt, a family of cathode materials that use neither nickel nor cobalt. — Nick Lichtenberg, Fortune, 15 Oct. 2026 Hydrogen forms at the cathode, while oxygen is produced at the anode. — New Atlas, 3 Sep. 2026 See All Example Sentences for cathode

Word History

Etymology

Greek kathodos way down, from kata- + hodos way

First Known Use

1834, in the meaning defined at sense 1

Time Traveler
The first known use of cathode was in 1834

Browse Nearby Words

Cite this Entry

“Cathode.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/cathode. Accessed 19 Oct. 2026.

Kids Definition

1
: the negative electrode of an electrolytic cell compare anode sense 1
2
: the positive terminal of a battery
3
: the electron-emitting electrode of an electron tube

Medical Definition

1
: the electrode of an electrochemical cell at which reduction occurs: as
a
: the negative terminal of an electrolytic cell
b
: the positive terminal of a storage battery that is delivering current
2
: the electron-emitting electrode of an electron tube compare anode

More from Merriam-Webster on cathode

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

More from Merriam-Webster