Akademik

1. A lack of transparency; an opaque or nontransparent area. 2. On a radiograph, a more transparent area is interpreted as an o. to x-rays in the body. 3. Mental dullness. [L. opacitas, shadiness]

- nodular o. a solitary, round, circumscribed shadow found in the lung on chest radiograph; causes include granuloma, primary or metastatic carcinoma, benign tumor, vascular malformation. SYN: coin lesion of lungs.

- snowball o. a spherical, white body seen in the vitreous in asteroid hyalosis.

opac·i·ty ō-'pas-ət-ē n, pl -ties

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)