notochord
noun
no·to·chord
ˈnō-tə-ˌkȯrd 
: a longitudinal flexible rod of cells that in the lowest chordates (such as a lancelet or a lamprey) and in the embryos of the higher vertebrates forms the supporting axis of the body
Examples of notochord in a Sentence
Recent Examples on the Web
Chordates share several common features, but the most notable is a flexible, supportive rod structure, or notochord, that runs down the animal’s length.
—
Elizabeth Rayne, Ars Technica, 16 July 2023
In 2016, researchers claimed to have identified a pale gut-like structure as a notochord, a primitive spine, signaling a vertebrate affinity.
—Jamie Dickman, Popular Science, 17 Apr. 2023
The tailfin and notochord — basically the sturgeon’s spine — is pulled out.
—oregonlive, 25 Aug. 2021
But that streak is important—it’s a notochord, or a precursor of our spinal column that marks Pikaia as one of the earliest relatives of vertebrates.
—Riley Black, Smithsonian Magazine, 10 Dec. 2020
But several fossils revealed that the band bore the hallmark traits of a notochord, the rubbery tube surrounding some primitive vertebrates’ spinal cords.
—Michael Greshko, National Geographic, 16 Mar. 2016
The very first step of this sequence is represented by chordates, or creatures with a notochord supporting their body.
—John Long, Discover Magazine, 12 June 2014
Instead what’s called a notochord, a flexible rod of tissue, extends along hagfish backs.
—Susan Milius, WIRED, 2 Mar. 2011
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Elizabeth Rayne, Ars Technica, 16 July 2023
In 2016, researchers claimed to have identified a pale gut-like structure as a notochord, a primitive spine, signaling a vertebrate affinity.
—Jamie Dickman, Popular Science, 17 Apr. 2023
The tailfin and notochord — basically the sturgeon’s spine — is pulled out.
—oregonlive, 25 Aug. 2021
But that streak is important—it’s a notochord, or a precursor of our spinal column that marks Pikaia as one of the earliest relatives of vertebrates.
—Riley Black, Smithsonian Magazine, 10 Dec. 2020
But several fossils revealed that the band bore the hallmark traits of a notochord, the rubbery tube surrounding some primitive vertebrates’ spinal cords.
—Michael Greshko, National Geographic, 16 Mar. 2016
The very first step of this sequence is represented by chordates, or creatures with a notochord supporting their body.
—John Long, Discover Magazine, 12 June 2014
Instead what’s called a notochord, a flexible rod of tissue, extends along hagfish backs.
—Susan Milius, WIRED, 2 Mar. 2011
Cite this Entry
“Notochord.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/notochord. Accessed 3 Nov. 2025.
Copy CitationKids Definition
notochord
noun
no·to·chord
ˈnōt-ə-ˌkȯ(ə)rd
: a flexible supporting rod of cells that exists in the embryos of all chordates, remains in the adults of some primitive forms (as lancelets and lampreys), and is replaced by the backbone in most vertebrates
Medical Definition
notochord
noun
no·to·chord
ˈnōt-ə-ˌkȯ(ə)rd
: a longitudinal flexible rod of cells that in the lowest chordates (as a lancelet or a lamprey) and in the embryos of the higher vertebrates forms the supporting axis of the body, that is almost obliterated in the adult of the higher vertebrates as the bodies of the vertebrae develop, and that arises as an outgrowth from the dorsal lip of the blastopore extending forward between epiblast and hypoblast in the middorsal line
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