neu·​ron ˈnü-ˌrän How to pronounce neuron (audio) ˈnyü- How to pronounce neuron (audio) ˈnu̇r-ˌän How to pronounce neuron (audio)
: a grayish or reddish granular cell that is the fundamental functional unit of nervous tissue transmitting and receiving nerve impulses and having cytoplasmic processes which are highly differentiated frequently as multiple dendrites or usually as solitary axons which conduct impulses to and away from the cell body : nerve cell sense 1
neuronal adjective
or less commonly neuronic

Illustration of neuron

Illustration of neuron
  • 1 cell body
  • 2 dendrite
  • 3 axon
  • 4 nerve ending

Example Sentences

Recent Examples on the Web Imagine that your brain is the football stadium, and each of the neurons is a person in that stadium. Marla Broadfoot, Smithsonian Magazine, 26 May 2023 The work builds on a flurry of recent studies that pinpoint specific populations of neurons in a region called the preoptic area (POA) of the hypothalamus. Byemily Underwood,, 25 May 2023 Of course, this doesn’t tell us why super agers have bigger, healthier entorhinal neurons, thicker anterior cingulates and shrink-resistant brains. Avery Hurt, Discover Magazine, 5 May 2023 Each octopus arm is thought to have around 10,000 neurons dedicated to sensing its surroundings. Kenna Hughes-castleberry, Ars Technica, 8 Apr. 2023 Then, the dermis, the middle layer of skin, consists of sweat glands, hair follicles, sensory neurons, and blood vessels. Melanie Rud, Health, 14 Mar. 2023 Enlarge Westend61 Sleep is a semiconscious state, but there are neurons firing in the brain even when all seems quiet. Elizabeth Rayne, Ars Technica, 9 May 2023 This is used to adjust the strength of connections, or weights, between neurons to improve prediction performance. IEEE Spectrum, 5 May 2023 As presented by the Australian Brain Alliance, our brains focus on neuron connections in the first months of our lives. Tim Newcomb, Popular Mechanics, 5 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'neuron.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


borrowed from German Neuron, borrowed from Greek neûron "sinew, tendon, nerve" — more at nerve entry 1

Note: Term introduced by the German anatomist Heinrich Wilhelm Waldeyer (Heinrich Wilhelm Gottfried von Waldeyer-Hartz, 1836-1921) in "Ueber einige neuere Forschungen im Gebiete der Anatomie der Centralnervensystems," Berliner klinische Wochenschrift, 28. Jahrgang, no. 28, July 13, 1891, p. 691: "Somit besteht ein Nervenelement (eine 'Nerveneinheit' oder 'Neuron', wie ich es zu nennen vorschlagen möchte), den genannten Forschungsergebnissen … zufolge, aus nachstehenden Stücken: a) einer Nervenzelle, b) dem Nervenfortsatze, c) dessen Collateralen und d) dem Endbäumchen." — "Therefore, in accordance with the cited research results, a nerve element (a 'nerve unit' or 'neuron,' as I would like to suggest as a name), consists of the following parts: a) a nerve cell, b) the nerve process [= axon], c) its collaterals and d) the end tree [= axon terminals]." Waldeyer apparently intended -on to be taken as a suffix, indicating a unit, rather than the Greek neuter singular inflectional ending, as he utilized Neuronen as the plural in the same article. Cf. French neurone and the English variant neurone.

First Known Use

1891, in the meaning defined above

Time Traveler
The first known use of neuron was in 1891

Dictionary Entries Near neuron

Cite this Entry

“Neuron.” Dictionary, Merriam-Webster, Accessed 10 Jun. 2023.

Kids Definition


: a grayish or reddish cell that is the basic working unit of the nervous system and has an axon and dendrites that carry nerve impulses

Medical Definition


variants also neurone
: one of the cells that constitute nervous tissue, that have the property of transmitting and receiving nerve impulses, and that are composed of somewhat reddish or grayish protoplasm with a large nucleus containing a conspicuous nucleolus, irregular cytoplasmic granules, and cytoplasmic processes which are highly differentiated frequently as multiple dendrites or usually as solitary axons and which conduct impulses toward and away from the cell body : nerve cell sense 1

More from Merriam-Webster on neuron

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