What is the meaning of Attenuation?

A gradual diminishing of strength.

A reduction in the level of some property with distance, especially the amplitude of a wave or the strength of a signal.

A weakening in the virulence of a pathogen or other microorganism.

The tapering of a leaf etc to a fine point.

A fabrication process in which a material is stretched out into a thin shape.

The reduction of the active principles of medicines to minute doses.

The proportion of sugar that is converted to ethanol by a yeast.

Source: wiktionary.org