Pe-nŭm’brȧ, n.

n. [Lat. pæne, almost, and umbra, shade; Sp. penumbra, It. penombra, Fr. pénombre.]

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.

☞ The faint shade surrounding the dark central portion of a solar spot is also sometimes called the penumbra, but more commonly the umbra. 3. (Paint.) The point of a picture where the shade blends with the light. Elmes.