Attenuation
Pronunciation : At*ten`u*a"tion
Part of Speech : n.
Etymology : [L. attenuatio: cf. F. att?nuation.]
Definition : 1. The act or process of making slender, or the state of being slender; emaciation.
2. The act of attenuating; the act of making thin or less dense, or of rarefying, as fluids or gases.
3. The process of weakening in intensity; diminution of virulence; as, the attenuation of virus.
Source : Webster's Unabridged Dictionary, 1913