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.
Florida immunization requirements for students include vaccines against polio, diphtheria, measles, mumps, rubella, hepatitis B among others. Raisa Habersham, Miami Herald, 26 Sep. 2025 For years, the GHC has had a presence in more than 60 countries (many of them low and middle income countries), leading efforts to combat diseases like polio, measles, HIV, tuberculosis, and neglected tropical diseases. Dr. Seth Berkley, Time, 26 Sep. 2025 These funds have gone toward everything from fighting diseases like polio and TB to environmental and educational projects in nations around the world. Eleanor Pringle, Fortune, 24 Sep. 2025 Keith Marple, an eighty-one-year-old Republican delegate from Harrison County, urged fellow-lawmakers to vote it down, and spoke of people he’d known with permanent complications of polio. Dhruv Khullar, New Yorker, 24 Sep. 2025 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 Sep. 2025.

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

More from Merriam-Webster on polio

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