Category:Penumbra

Pe*num"bra, n. Etym: [nl., fr. L. paene almost + umbra shade.]

1. An incomplete or partial shadow.

2. (astron.)

Defn: the shadow cast, in an eclipse, where the light is partly, but Not wholly, cut off by the intervening body; the space of partial Illumination between the umbra, or perfect shadow, on all sides, and The full light. Sir i. Newton.

Note: the faint shade surrounding the dark central portion of a solar Spot is also called the penumbra, and sometimes umbra.

3. (paint.)

Defn: the part of a picture where the shade imperceptibly blends with The light.