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

Vote no on proposals that ask a person with Down syndrome to prove their disability twice a year. —Joseph MacBeth, Sun Sentinel, 22 June 2025

The Arc of San Diego serves more than 2,000 children and adults with intellectual and developmental disabilities such as autism, cerebral palsy, and Down syndrome each year. —San Diego Union-Tribune, 19 June 2025

Genetic disease impacts millions of children in the U.S., with Down syndrome, Thalassemia, cystic fibrosis, Tay-Sachs disease and sickle cell disease among the most common. —Jasmine Laws, MSNBC Newsweek, 19 June 2025

Genetic disorders: Certain conditions, such as Down syndrome and Klinefelter syndrome, may increase the risk of AML. —Health, 24 May 2025

Word History

Etymology

J. L. H. Down †1896 English physician

First Known Use

1961, in the meaning defined above

Rhymes for Down syndrome

• acrosome
• aerodrome
• catacomb
• centrosome
• chromosome
• cytochrome
• hippodrome
• honeycomb
• liposome
• meerschaum
• metronome
• microtome

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