nervous systemn. The system of cells, tissues, and organs that regulates the body’s responses to internal and external stimuli. In vertebrates it consists of the brain, spinal cord, nerves, ganglia, and parts of the receptor and effector organs.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.nervous system n (Physiology) the sensory and control apparatus of all multicellular animals above the level of sponges, consisting of a network of nerve cells. See neurone See also central nervous system Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014nerv?ous sys`tem n. the system of neurons, neurochemicals, and allied structures involved in receiving sensory stimuli, generating and coordinating responses, and controlling bodily activities: in vertebrates it includes the brain, spinal cord, nerves, and ganglia. [1730?40] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.nerv·ous system (nûr?v?s) The system of nerve cells and tissues that regulates the actions and responses of vertebrate and many invertebrate animals. The nervous system of vertebrates consists mainly of the brain, spinal cord, and nerves. The nervous systems of invertebrates vary from a simple network of nerves to a complex nerve network under the control of a primitive brain. See also autonomic nervous system, central nervous system, peripheral nervous system.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.nervous systemThe coordinated networks of neurons that control the body. See autonomic nervous system, central nervous system, peripheral nervous system.Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited