Down syndrome

noun

variants or Down's syndrome
: a congenital condition characterized especially by developmental delays, usually mild to moderate impairment in cognitive functioning, short stature, upward slanting eyes, a flattened nasal bridge, broad hands with short fingers, decreased muscle tone, and by trisomy of the human chromosome numbered 21

called also trisomy 21

Examples of Down syndrome in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Hundreds have commented with overwhelming support and many others shared their own experiences with Down syndrome. Daniella Gray, MSNBC Newsweek, 21 July 2025 People with intellectual disabilities, such as those with Down syndrome or fetal alcohol spectrum disorder, have historically had shorter life expectancies than the general population, but data from a Population Reference Bureau study found that the gap is shrinking. Karen Fonseth, Forbes.com, 18 July 2025 Courtney and Spencer Morey sued the Aledo Independent School District last year, arguing that the district was violating the Americans with Disabilities Act by denying special education services to their 4-year-old daughter, Annie, who has Down syndrome. Silas Allen, Fort Worth Star-Telegram, 17 July 2025 But Shannon French, a Meridian single mother who provided care for her children with Down syndrome and autism, argued that ending the program would just push families to rely more on other social programs. Sarah Cutler updated July 16, Idaho Statesman, 16 July 2025 See All Example Sentences for Down syndrome

Word History

Etymology

J. L. H. Down †1896 English physician

First Known Use

1961, in the meaning defined above

Time Traveler
The first known use of Down syndrome was in 1961

Browse Nearby Words

Cite this Entry

“Down syndrome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Down%20syndrome. Accessed 1 Aug. 2025.

Kids Definition

Down syndrome

noun
ˈdau̇n-
variants or Down's syndrome
ˈdau̇n(z)-
: a genetic condition characterized especially by developmental delays, by distinctive physical traits (as short stature and upward slanting eyes), and by the presence of three chromosomes numbered 21 in human beings
Etymology

named for J.L.H. Down, 1828–1896, English doctor

Medical Definition

Down syndrome

noun
variants or Down's syndrome
: a congenital condition characterized especially by developmental delays, usually mild to moderate impairment in cognitive functioning, short stature, relatively small head, upward slanting eyes usually with epicanthal folds, flattened nasal bridge, broad hands with short fingers, decreased muscle tone, and by trisomy of the human chromosome numbered 21

called also Down, Down's, trisomy 21

More from Merriam-Webster on Down syndrome

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!