opacity

opac·i·ty

noun \ō-ˈpas-ət-ē\

plural opac·i·ties

Definition of OPACITY

1

: the quality or state of a body that makes it impervious to the rays of light; broadly : the relative capacity of matter to obstruct by absorption or reflection the transmission of radiant energy (as X-rays, infrared radiation, or sound)

2

: an opaque spot in a normally transparent structure (as the lens of the eye)