nerve cord
noun
1
: the pair of closely united ventral longitudinal nerves with their segmental ganglia that is characteristic of many elongate invertebrates (such as earthworms)
2
: the dorsal tubular cord of nervous tissue above the notochord of a chordate that comprises or develops into the central nervous system
Example Sentences
Recent Examples on the Web Our closest non-vertebrate relatives re-established a nerve cord (on the wrong side of the body, naturally) but couldn't be bothered with niceties like a skeleton. 
John Timmer, Ars Technica, 7 July 2022 So, the presence of cartilage suggests that, even at this early stage of their evolution, vertebrates probably had a distinct nerve cord that produced a neural crest—something that our close relatives like the amphioxus doesn't have. John Timmer, Ars Technica, 7 July 2022 The critters can’t control each leg individually (imagine that traffic jam), but instead use a single nerve cord that travels the length of their body to coordinate the movement. Haley Weiss, The Atlantic, 16 Dec. 2021 Yet retinoic acid signaling was thought to be essential for making a brain, nerve cord and other vital features. Quanta Magazine, 1 Sep. 2020 The FlyEM group is now working on constructing a circuit diagram of the fruit fly’s full nervous system—which consists of the entire brain and nerve cord, a spinal cordlike structure in the insect. Diana Kwon, Scientific American, 22 Jan. 2020 Along this nerve cord are inhibitory neurons that act as gatekeepers, allowing pain signals through or blocking them based on context. Jason Daley, Smithsonian, 17 July 2019 See More
John Timmer, Ars Technica, 7 July 2022 So, the presence of cartilage suggests that, even at this early stage of their evolution, vertebrates probably had a distinct nerve cord that produced a neural crest—something that our close relatives like the amphioxus doesn't have. John Timmer, Ars Technica, 7 July 2022 The critters can’t control each leg individually (imagine that traffic jam), but instead use a single nerve cord that travels the length of their body to coordinate the movement. Haley Weiss, The Atlantic, 16 Dec. 2021 Yet retinoic acid signaling was thought to be essential for making a brain, nerve cord and other vital features. Quanta Magazine, 1 Sep. 2020 The FlyEM group is now working on constructing a circuit diagram of the fruit fly’s full nervous system—which consists of the entire brain and nerve cord, a spinal cordlike structure in the insect. Diana Kwon, Scientific American, 22 Jan. 2020 Along this nerve cord are inhibitory neurons that act as gatekeepers, allowing pain signals through or blocking them based on context. Jason Daley, Smithsonian, 17 July 2019 See More Word History
First Known Use
1877, in the meaning defined at sense 1
Medical Definition
nerve cord
noun
: the dorsal tubular cord of nervous tissue above the notochord of a chordate that in vertebrates includes or develops an anterior enlargement comprising the brain and a more posterior part comprising the spinal cord with the two together making up the central nervous system