nervous system
Americannoun
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the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia.
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a particular part of this system.
noun
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The system of neurons and tissues that regulates the actions and responses of vertebrates and many invertebrates. The nervous system of vertebrates is a complex information-processing system that consists mainly of the brain, spinal cord, and peripheral and autonomic nerves. It receives chemical information from hormones in the circulating blood and can also regulate secretions of the endocrine system by the action of neurohormones. The nervous systems of invertebrates vary from a simple network of nerves to a complex nerve network under the control of a primitive brain.
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See also autonomic nervous system central nervous system peripheral nervous system
Etymology
Origin of nervous system
First recorded in 1730–40
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Chips, cloud computing and AI "are the nervous system of the modern economy", powering everything from defence to healthcare, EU lawmaker Oliver Schenk said.
From Barron's • Jun. 3, 2026
Studies have also shown adverse effects on the nervous system, reproduction, the hormonal system and the functioning of certain organs including the heart, according to ANSES.
From Barron's • Jun. 2, 2026
The gut microbiome can produce compounds that influence inflammation, metabolism, and nervous system activity.
From Science Daily • May 31, 2026
Nearly 7,000 people in Wales live with MS, which affects the central nervous system and can cause symptoms including blurred vision and mobility problems.
From BBC • May 29, 2026
Besides, that procession of terrifying figures was destroying Barrabas’s nervous system.
From "The House of the Spirits: A Novel" by Isabel Allende
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.