chromosome

noun

chro·​mo·​some ˈkrō-mə-ˌsōm 

-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

ˌkrō-mə-ˈsō-məl 

-ˈzō-

adjective

chromosomally

ˌkrō-mə-ˈsō-mə-lē 

-ˈzō-

adverb

Examples of chromosome in a Sentence

Recent Examples on the Web

Prenatal genetic testing is done to screen for genetic conditions known as fetal aneuploidy, such as Down syndrome, in which a fetus has one or more extra chromosomes or the absence of one or more chromosomes. —Jacqueline Howard, CNN, 16 Dec. 2024

As the embryo develops, cells randomly choose which chromosome to express, or make visible, on different parts of the cat’s pelt. —Gayoung Lee, Smithsonian Magazine, 10 Dec. 2024

Cayden Addison, a seven-year-old Black boy battling a rare form Philadelphia chromosome acute lymphocytic leukemia (ALL), has had two donors back out on him. —Pia Velasco, Vogue, 4 Nov. 2024

Like the Dutch study, IDENTIFY detected some specific kinds of DNA abnormalities, including gains and losses of multiple chromosomes, that were much more likely to be seen in the people with cancer, whereas other patterns were associated with less worrying outcomes like uterine fibroids. —Byjennifer Couzin-Frankel, science.org, 4 Dec. 2024

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

Phrases Containing chromosome

• chromosome number
• lampbrush chromosome
• sex chromosome
• X chromosome
• Y chromosome

Kids Definition

chromosome

noun

chro·​mo·​some ˈkrō-mə-ˌsōm 

-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

ˌkrō-mə-ˈsō-məl 

-ˈzō-

adjective

Medical Definition

chromosome

noun

chro·​mo·​some ˈkrō-mə-ˌsōm, -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 (as bacteria), and contain all or most of the genes of the organism

also : the genetic material of a virus

chromosomal

ˌkrō-mə-ˈsō-məl, -ˈzō- 

adjective

chromosomally

-mə-lē 

adverb