Definition of "myasthenia" [myasthenia]

• Abnormal muscular weakness or fatigue. (noun)
• Myasthenia gravis. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The CDC report released by the New England Journal of Medicine said the Mexican toddler had a chronic muscle weakness called myasthenia gravis, a heart defect, a swallowing problem and lack of oxygen."
• "He said his health - he suffers from muscular weakness called myasthenia gravis - seemed to be getting back into shape with the aid of drugs and exercise."
• "She developed a muscular disorder called myasthenia gravis and underwent a kidney transplant in 1990."