my·​as·​the·​nia ˌmī-əs-ˈthē-nē-ə How to pronounce myasthenia (audio)
: muscular debility
myasthenic adjective or noun

Example Sentences

Recent Examples on the Web Patients with myasthenia have muscles that tire out much more quickly than normal. New York Times, 4 Mar. 2021 Keung wasn’t certain that the patient had myasthenia. New York Times, 4 Mar. 2021 That doctor argued that although myasthenia often causes weakness in the muscles of the eyes and mouth — not unlike what this woman had — that weakness usually comes and goes. Lisa Sanders, M.d., New York Times, 26 Sep. 2017 His death at the age of 74 came after a long battle with the physically debilitating illness myasthenia gravis and after a public-service career that spanned four decades. Sheldon S. Shafer, The Courier-Journal, 7 July 2017 Smith had battled the nerve disease myasthenia gravis for many years. Joseph Longo,, 6 June 2017 Mr. Smith, who had given up performing to manage his wife’s career, had been diagnosed with myasthenia gravis, an autoimmune neuromuscular disease that causes extreme weakness. Adam Bernstein, Washington Post, 5 June 2017 After a year and a half of tests and several brutal eye surgeries, he was given a diagnosis of myasthenia gravis, a rare autoimmune disease that interferes with the way nerves and muscles communicate. Kim Severson, New York Times, 3 July 2017 Trollious Harris, who has spent most of her life a few blocks from the Taylors, suffers from myasthenia gravis, another autoimmune condition, which has caused her muscles to weaken. Charles P. Pierce, Esquire, 19 May 2017 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'myasthenia.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


New Latin

First Known Use

circa 1833, in the meaning defined above

Time Traveler
The first known use of myasthenia was circa 1833

Dictionary Entries Near myasthenia

Cite this Entry

“Myasthenia.” Dictionary, Merriam-Webster, Accessed 5 Dec. 2022.

Medical Definition



my·​as·​the·​nia ˌmī-əs-ˈthē-nē-ə How to pronounce myasthenia (audio)
: muscular debility
myasthenic adjective

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