Barr body

noun

: a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is used as a test of genetic femaleness (as in a fetus)

called also sex chromatin

Examples of Barr body in a Sentence

Recent Examples on the Web
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The inactivated chromosome can be seen under a microscope as a tiny dark Barr body compacted inside cells. Grrlscientist, Forbes.com, 2 June 2025

Word History

Etymology

Murray Llewellyn Barr †1995 Canadian anatomist

First Known Use

1961, in the meaning defined above

Time Traveler
The first known use of Barr body was in 1961

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Cite this Entry

“Barr body.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Barr%20body. Accessed 18 Jun. 2025.

Medical Definition

Barr body

noun
: a densely staining inactivated condensed X chromosome that is present in each somatic cell of most female mammals and is used as a test of genetic femaleness (as in a fetus or an athlete)

called also sex chromatin

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