chromosome

American  

[kroh-muh-sohm] / ˈkroʊ məˌsoʊm /

noun

Genetics.

• chromosomes
  plural

1. any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear order: the human species has 23 pairs, designated 1 to 22 in order of decreasing size and X and Y for the sex-determining chromosomes.

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chromosome British  

/ ˈkrəʊməˌsəʊm /

noun

1. any of the microscopic rod-shaped structures that appear in a cell nucleus during cell division, consisting of nucleoprotein arranged into units (genes) that are responsible for the transmission of hereditary characteristics See also homologous chromosomes

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chromosome Scientific  

/ krō′mə-sōm′ /

1. A structure in all living cells that consists of a single molecule of DNA bonded to various proteins and that carries the genes determining heredity. In all eukaryotic cells, the chromosomes occur as threadlike strands in the nucleus. During cell reproduction, these strands coil up and condense into much thicker structures that are easily viewed under a microscope. Chromosomes occur in pairs in all of the cells of eukaryotes except the reproductive cells, which have one of each chromosome, and some red blood cells (such as those of mammals) that expel their nuclei. In bacterial cells and other prokaryotes, which have no nucleus, the chromosome is a circular strand of DNA located in the cytoplasm.

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Other Word Forms

Derived Forms

• chromosomal
  adjective
• interchromosomal
  adjective
• nonchromosomal
  adjective
• chromosomally
  adverb
• interchromosomally
  adverb

Inflected Forms

Nouns

• chromosomes
  plural

Etymology

Origin of chromosome

First recorded in 1885–90; chromo- + -some ³

Compare meaning

How does chromosome compare to similar and commonly confused words? Explore the most common comparisons:

• chromosome vs. chromatid
• chromatin vs. chromosome
• plasmid vs. chromosome

Explanation

A chromosome is a strand of DNA that is encoded with genes. In most cells, humans have 22 pairs of these chromosomes plus the two sex chromosomes (XX in females and XY in males) for a total of 46. The word chromosome was originally coined in German from the Greek words khroma, meaning "color," and soma meaning "body." In the late 1800s, a scientist, Wilhelm von Waldeyer-Hartz, gave chromosomes their name because chromosomes easily accept dye and take on patterns of light and dark when exposed to different stains that help identify the different chromosomes.

Example Sentences

See Examples For:

chromosome chromosomes

As chromosome mixing accumulates over time, lineages continue to diverge.

From Science Daily ● Aug. 25, 2026

The Year 8 student from Western Australia has Down Syndrome – a genetic condition caused by an extra copy of chromosome 21 which leads to physical and intellectual disabilities.

From BBC ● Aug. 12, 2026

Down's syndrome is when you're born with an extra chromosome - and people with the condition are likely to have some level of learning disability.

From BBC ● Jul. 26, 2026

A depletion of Neanderthal DNA on the X chromosome may, therefore, reflect a classic biological phenomenon, not the lingering trace of an erotic choice.

From Science Daily ● Jul. 7, 2026

Working with mustard gas, they found that this chemical produces permanent chromosome abnormalities that cannot be distinguished from those induced by radiation.

From "Silent Spring" by Rachel Carson

They can reveal which genes an animal possesses without showing exactly where those genes are positioned along its chromosomes.

From Science Daily ● Aug. 25, 2026

It occurs when two chromosomes join, and their genes become intermixed.

From Science Daily ● Aug. 25, 2026

Instead, most were located on autosomes, the non sex chromosomes shared by males and females.

From Science Daily ● Aug. 20, 2026

Under this genetic system, females develop from fertilized eggs and possess two sets of chromosomes, while males develop from unfertilized eggs and have only one set.

From Science Daily ● Aug. 15, 2026

“Well, good job hashtag-educated-guessing, but it’s actually telophase two. See, the chromosomes have been divided into four separate haploids.”

From "The Science of Breakable Things" by Tae Keller