<p><strong>Noun:</strong></p><ul><li>The act of attenuating or the state of being attenuated.</li><li>The process by which a virus, bacterium, etc., changes under laboratory conditions to become harmless or less virulent.</li><li>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.</li></ul>