An Attenuation

1. A gradual diminishing of strength.
2. (physics) A reduction in the level of some property with distance, especially the amplitude of a wave or the strength of a signal.
3. (biology) A weakening in the virulence of a pathogen or other microorganism.
4. (botany) The tapering of a leaf etc to a fine point.
5. (engineering) A fabrication process in which a material is stretched out into a thin shape.
6. (homeopathy) The reduction of the active principles of medicines to minute doses.
7. (brewing) The proportion of sugar that is converted to ethanol by a yeast.