chromosome

noun

chro·​mo·​some ˈkrō-mə-ˌsōm How to pronounce chromosome (audio)
-ˌzōm
: any of the rod-shaped or threadlike DNA-containing structures of cellular organisms that are located in the nucleus of eukaryotes, are usually ring-shaped in prokaryotes (such as bacteria), and contain all or most of the genes of the organism
also : the genetic material of a virus compare chromatin
chromosomal adjective
chromosomally adverb

Examples of chromosome in a Sentence

Recent Examples on the Web The majority of embryos implanted by IVF don’t develop into babies, often due to chromosome or genetic defects. Daniel Gilbert, Washington Post, 7 Mar. 2024 Left unfixed, these strands can snag at and break chromosomes, leading to diseases like cancer and other disorders. William A. Haseltine, Forbes, 25 Feb. 2024 In 1998, my group at Saint Barnabas Medical Center in suburban New Jersey was part of a team that developed a way to test for a genetic variant called a translocation, a swapping of parts of one chromosome with a different chromosome. David Sable, STAT, 22 Feb. 2024 Down syndrome occurs when a genetic mutation causes two copies of chromosome 21 to form, resulting in physical and developmental changes, the study authors said in a Feb. 20 statement. Irene Wright, Miami Herald, 20 Feb. 2024 Researchers also identified an infant with an extra copy of chromosome 18, indicating a condition called Edwards syndrome, at one of the Bronze Age Spanish sites. Catherine Duncan, Smithsonian Magazine, 27 Feb. 2024 Such testing can also identify which embryos have a normal number of chromosomes and are less likely to result in a miscarriage. Sabrina Malhi, Washington Post, 21 Feb. 2024 Subsequent research revealed that patients wound up with the Philadelphia chromosome as a result of a rare translocation event wherein chromosome 9 and chromosome 22 mistakenly swapped segments during cell division. WIRED, 4 Sep. 2023 Testing the ‘significant role’ of Xist The Xist molecule’s main job is to deactivate the second female X chromosome in embryos, ensuring that the body’s cells don’t get a potentially toxic double whammy of the chromosome’s protein-coding genes. Katie Hunt, CNN, 9 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'chromosome.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

borrowed from German Chromosom, from chromo- chromo- + -som -some entry 3

Note: The term Chromosom was first suggested by the German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz in "Ueber Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen," Archiv für mikroskopische Anatomie, Band 23 (1888), p. 27: "In ester Linier möchte ich mir jedoch den Vorschlag erlauben, diejenigen Dinge, welche soeben mit Boveri als 'chromatische Elemente' bezeichnet wurden, an denen sich einer der wichtigsten Akten der Karyokinese, die Flemming'sche Längsteilung vollzieht, mit einem besonderen terminus technicus 'Chromosomen' zu belegen. Der Name 'primäre Schleifen' passt nicht, da wir bei weitem nicht immer eine Schleifenform für diese Dinge haben. 'Chromatische Elemente' ist zu lang. Andererseits sind sie so wichtig, dass ein besonderer kürzerer Name wünschenswerth erscheint. Plattne … gebraucht den Ausdruck 'Karyosomen'; da dieser aber zu sehr an Kernkörperchen erinnert, dürfte eine andere Bezeichnung vorzuziehen sein. Ist die von mir vorgeschlagene praktisch verwendbar, so wird sie sich wohl einbürgern, sonst möge sie bald der Vergessenheit anheimfallen." ("In the first place I must allow myself to suggest a new technical term, 'chromosomes,' for those things which have been designated by Boveri 'chromatic elements,' at which one of the most important acts of karyokinesis, Flemming's longitudinal splitting, is carried out. The name 'primary loops' is not suitable, since it is by no means the case that these things always have the form of a loop. 'Chromatic elements' is too long. On the other hand, they are so important that a special shorter name seems desirable. Plattner uses the expression 'karyosomes,' but as this too readily brings to mind nucleoli, another name is to be preferred. If the name I propose is serviceable, it will become customary, otherwise it will soon pass into oblivion.")

First Known Use

1889, in the meaning defined above

Time Traveler
The first known use of chromosome was in 1889

Dictionary Entries Near chromosome

Cite this Entry

“Chromosome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/chromosome. Accessed 19 Mar. 2024.

Kids Definition

chromosome

noun
chro·​mo·​some ˈkrō-mə-ˌsōm How to pronounce chromosome (audio)
-ˌzōm
: one of the rod-shaped or threadlike DNA-containing bodies of a cell nucleus that contain all or most of the genes of an organism and can be seen especially during cell division
chromosomal adjective

Medical Definition

chromosome

noun
chro·​mo·​some ˈkrō-mə-ˌsōm, -ˌzōm How to pronounce chromosome (audio)
: any of the rod-shaped or threadlike DNA-containing structures of cellular organisms that are located in the nucleus of eukaryotes, are usually ring-shaped in prokaryotes (as bacteria), and contain all or most of the genes of the organism
also : the genetic material of a virus
chromosomal adjective
chromosomally adverb

More from Merriam-Webster on chromosome

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