pen·um·bra /pəˈnʌmbrə/
 半影
 pe·num·bra /pəˈnəmbrə/ 名詞
 Pe·num·bra n.
 1. An incomplete or partial shadow.
 2. Astron. 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.
 Note: ☞ The faint shade surrounding the dark central portion of a solar spot is also called the penumbra, and sometimes umbra.
 3. Paint. The part of a picture where the shade imperceptibly blends with the light.
 ◄ ►
 penumbra
      n : a fringe region of partial shadow around an umbra
      [also: penumbrae (pl)]