penumbra
noun
- the partially shaded outer region of a shadow, especially from an eclipse, or a figurative area of uncertain boundaries.
- During the partial eclipse, the moon's penumbra cast a faint shadow over the landscape.
- Observers stood in the penumbra, where the light was dim but not completely blocked.
- The penumbra of legal ambiguity made the contract difficult to enforce.
- The artist used the penumbra effect to create a soft transition between light and dark.