polio

noun

po·​lio ˈpō-lē-ˌō How to pronounce polio (audio)
: an infectious disease especially of young children that is caused by the poliovirus

Note: Individuals infected with the poliovirus are often asymptomatic. In approximately 25% of cases, polio presents as a mild to moderate illness marked by headache, fever, sore throat, vomiting, diarrhea, and fatigue. Polio affects the central nervous system only infrequently with inflammation and sometimes destruction of the motor neurons in the gray matter of the spinal cord and brain stem. Central nervous system involvement results in temporary or permanent muscle weakness or motor paralysis especially of the limbs and typically the legs. Polio may become life-threatening when paralysis affects the muscles involved in breathing and swallowing.

And the dreaded disease polio was virtually eliminated in 1955 when the Salk vaccine was approved for public use.Mary Beth Norton et al.
The longstanding quest to eradicate polio is attracting a new injection of funds from donors around the world, as health leaders grapple with obstacles from ridding conflict areas of the virus to a shortage of vaccine.Betsy McKay

called also infantile paralysis, poliomyelitis

see post-polio syndrome
polio-like adjective
or poliolike
a polio-like disease
polio-like paralysis

Examples of polio 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.
The unexpected trade off was lives saved from COVID in the short term versus future lives potentially lost to measles, pertussis, polio, RSV, influenza and other preventable diseases. Literary Hub, 23 Mar. 2026 The Gates Foundation funding was to support a polio eradication campaign in parts of rural Pakistan and Afghanistan, where years of vaccination progress had been undone after a CIA operation in Pakistan in which agents posed as vaccinators while hunting for Osama bin Laden. Clara Molot, Vanity Fair, 19 Mar. 2026 The virus was traced to Nigeria, where religious and political leaders in some areas had boycotted polio immunization campaigns amid false rumors that the shots had been tainted to make Muslim girls infertile. Patricia Callahan, ProPublica, 19 Mar. 2026 The politician said his father immigrated to the United States from South Korea 50 years ago and was born with polio. Christine Sloan, CBS News, 12 Mar. 2026 See All Example Sentences for polio

Word History

Etymology

short for poliomyelitis

First Known Use

1911, in the meaning defined above

Time Traveler
The first known use of polio was in 1911

Browse Nearby Words

Cite this Entry

“Polio.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/polio. Accessed 30 Mar. 2026.

Kids Definition

polio

noun
po·​lio ˈpō-lē-ˌō How to pronounce polio (audio)

Medical Definition

polio

noun
po·​lio ˈpō-lē-ˌō How to pronounce polio (audio)
: an infectious disease especially of young children that is caused by the poliovirus

Note: Individuals infected with the poliovirus are often asymptomatic. In approximately 25% of cases, polio presents as a mild to moderate illness marked by headache, fever, sore throat, vomiting, diarrhea, and fatigue. Polio affects the central nervous system only infrequently with inflammation and sometimes destruction of the motor neurons in the gray matter of the spinal cord and brain stem. Central nervous system involvement results in temporary or permanent muscle weakness or flaccid paralysis of muscles especially of the limbs and typically the legs. Polio may become life-threatening when paralysis affects the muscles involved in breathing and swallowing.

Thanks to the Salk and Sabin vaccines, the specter of crippling polio that once made summers an apprehensive time for Americans has long since passed.People Weekly
While the last case of naturally occurring polio in the United States was in 1979, the disease remains prevalent in other areas of the world.Evan Johnson, The Addison County (Vermont) Independent

called also infantile paralysis, poliomyelitis

see post-polio syndrome

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