from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Abnormal muscular weakness or fatigue.
- n. Myasthenia gravis.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Abnormal weakness of the muscles; but especially myasthenia gravis
from The Century Dictionary and Cyclopedia
- n. Muscular debility.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a chronic progressive disease characterized by chronic fatigue and muscular weakness (especially in the face and neck); caused by a deficiency of acetylcholine at the neuromuscular junctions
- n. any muscular weakness
my- (“relating to muscle”) + asthenia (“weakness”), from Ancient Greek ἀσθένεια (asthénia, "weakness") (Wiktionary)