chromosome

American  

[kroh-muh-sohm] / ˈkroʊ məˌsoʊm /

noun

Genetics.

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

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

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

Example Sentences

"While the direct evidence of physical advantage in transgender people is pretty strong, the evidence of advantage for those with DSD, even though they have a Y chromosome, is highly disputed."

From BBC • Mar. 31, 2026

These genes also have counterparts on the X chromosome, meaning both males and females typically have two copies.

From Science Daily • Mar. 20, 2026

It remains challenging to determine whether losing the Y chromosome directly causes disease or simply occurs alongside it.

From Science Daily • Mar. 20, 2026

Advances in genetic detection have revealed that Y chromosome loss is widespread in older men.

From Science Daily • Mar. 20, 2026

Let us return to linkage: Morgan’s experiments had established that genes that were physically linked to each other on the same chromosome were inherited together.

From "The Gene" by Siddhartha Mukherjee