D defs.my
Entry 3 senses Webster, 1913

Attenuation

/ət-ĕnˌ-yo͞o-āsh'-ən/ · At·ten·u·a·tion · IPA /ətˌɛnjuːˈeɪʃən/
01 n. The act or process of making slender, or the state of being slender; emaciation.
  1. 1.
    The act or process of making slender, or the state of being slender; emaciation.
  2. 2.
    The act of attenuating; the act of making thin or less dense, or of rarefying, as fluids or gases.
  3. 3.
    The process of weakening in intensity; diminution of virulence; as, the attenuation of virus.