attenuation

noun

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. Physics. 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.

noun

1. the act of attenuating or the state of being attenuated
2. the loss of energy suffered by radiation as it passes through matter, esp as a result of absorption or scattering

n.

early 15c., of persons, “emaciation;” of diet, “reduction,” from Latin attenuationem (nominative attenuatio) “a lessening,” noun of action from past participle stem of attenuare (see attenuate).

n.

1. A dilution, thinning, or weakening of a substance, especially a reduction in the virulence of a pathogen through repeated inoculation, growth in a different culture medium, or exposure to heat, light, air, or other weakening agents.
2. The energy loss of an ultrasonic beam as it passes through a material.