Attenuation

n. reduction; weakening; decrease; diminution; being weakened; weakening of a signal as the length of a network cable increases (Computers)

Attenuation is the reduction in amplitude and intensity of a signal. Signals may be attenuated exponentially by transmission through a medium, in which case attenuation is usually reported in dB with respect to distance traveled through the medium. Attenuation can also be understood to be the opposite of amplification. Attenuation is an important property in telecommunications and ultrasound applications because of its importance in determining signal strength as a function of distance. Attenuation is usually measured in units of decibels per unit length of medium (dB/cm, dB/km, etc) and is represented by the attenuation coefficient of the medium in question.
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Noun
1. weakening in force or intensity; "attenuation in the volume of the sound"
(synonym) fading
(hypernym) weakening
(derivation) attenuate
2. the property of something that has been weakened or reduced in thickness or density
(hypernym) weakness
(derivation) rarefy, attenuate

n. attenuation, extenuation; dimming, mitigation

(n.)
The process of weakening in intensity; diminution of virulence; as, the attenuation of virus.
  

(n.)
The act or process of making slender, or the state of being slender; emaciation.
  

(n.)
The act of attenuating; the act of making thin or less dense, or of rarefying, as fluids or gases.