neuronneu·ron (no?or??n?, nyo?or?-)n.1. Any of the impulse-conducting cells that constitute the brain, spinal column, and nerves in vertebrates, consisting of a nucleated cell body with one or more dendrites and a single axon.2. A similar impulse-conducting cell in invertebrates. In both senses also called nerve cell.[Greek, sinew, string, nerve; see (s)ne?u- in Indo-European roots.]neu?ro·nal (no?or??-n?l, nyo?or?-, no?o-r?n?l, nyo?o-), neu·ron?ic adj.neu?ro·nal·ly adv.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.neu?ron (?n??r ?n, ?ny??r-) n. a specialized, impulse-conducting cell that is the functional unit of the nervous system, consisting of the cell body and its processes, the axon and dendrites. Also called nerve cell. Also, esp. Brit.,neu?rone (-o?n) [1880?85;