altitude sickness

noun

: the effects (such as headache, nausea, or swelling of the brain) of oxygen deficiency in the blood and tissues developed at high altitudes having reduced atmospheric pressure see mountain sickness

Examples of altitude sickness in a Sentence

Recent Examples on the Web
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The agency also noted that mountaineers must also deal with altitude sickness due to the high elevation levels of the mountain. Kimberlee Speakman, People.com, 5 June 2025 More on altitude sickness, risks of climbing Mount Fuji Mount Fuji was created from volcanic activity that started 100,000 years ago, per the Japan National Tourism Organization. Saleen Martin, USA Today, 31 Oct. 2024 On their ascent, one of the team members, a Nepali soldier named Narayan Singh, showed signs of altitude sickness. Ben Ayers and Tulsi Rauniyar, Outside Online, 7 May 2024 Even dosing people with EPO directly with injections may not prevent altitude sickness or improve performance at high elevation, Subudhi says. Stephanie Pappas, Scientific American, 29 May 2025 See All Example Sentences for altitude sickness

Word History

First Known Use

1901, in the meaning defined above

Time Traveler
The first known use of altitude sickness was in 1901

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Cite this Entry

“Altitude sickness.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/altitude%20sickness. Accessed 4 Jul. 2025.

Medical Definition

altitude sickness

noun
al·​ti·​tude sickness ˌal-tə-ˌt(y)üd- How to pronounce altitude sickness (audio)
: the effects (as nosebleed, nausea, headache, or cerebral edema) of oxygen deficiency in the blood and tissues developed at high altitudes with reduced atmospheric pressure

More from Merriam-Webster on altitude sickness

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