At*ten`u*a"tion (#), n. [L. attenuatio: cf. F. att'enuation.]
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.
© Webster 1913.