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.
The 44-year-old Los Angeles resident says the peptides have helped with myriad symptoms she has long struggled with due to a disorder of her autonomic nervous system.
From The Wall Street Journal • Apr. 20, 2026
If it’s uncomfortable or unsustainable to live with continuously, ask your body why — and how it can help you make decisions that are the kindest possible to your nervous system.
From Los Angeles Times • Apr. 10, 2026
Platts said while most people associate radiation with cancer risk, it also can impact the central nervous system and blood circulation.
From Barron's • Apr. 10, 2026
It has been linked to behavioral issues, damage to the brain and central nervous system, and other health problems.
From Science Daily • Apr. 2, 2026
The deciduous trees stood up in skeleton, like maps of the veins or of the nervous system.
From "The Once and Future King" by T. H. White
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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.