) KEY NOUN: pl. pe·num·brae
- A partial shadow, as in an eclipse, between regions of complete shadow and complete illumination. See Synonyms at shade.
- The grayish outer part of a sunspot.
- An area in which something exists to a lesser or uncertain degree: "The First Amendment has a penumbra where privacy is protected from governmental intrusion" (Joseph A. Califano, Jr.).
- An outlying surrounding region; a periphery: "Downtown Chicago and its penumbra also stand rejuvenated" (John McCormick).
New Latin pnumbra
: Latin paene
+ Latin umbra
, shadowOTHER FORMS:pe·numbral