attenuation: Meaning and Definition of

at•ten•u•a•tion

Pronunciation: (u-ten"y-ā'shun), [key]
— n.
  1. the act of attenuating or the state of being attenuated.
  2. the process by which a virus, bacterium, etc., changes under laboratory conditions to become harmless or less virulent.
  3. a decrease in a property, as energy, per unit area of a wave or a beam of particles, occurring as the distance from the source increases as a result of absorption, scattering, spreading in three dimensions, etc.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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