1. A sudden, involuntary contraction of a muscle or group of muscles.
2. A sudden burst of energy, activity, or emotion.

[Middle English spasme, from Old French, from Latin spasmus, from Greek spasmos, from spān, to pull.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.