penumbral


penumbra

pe·num·bra

P0175400 (pĭ-nŭm′brə)n. pl. pe·num·bras or pe·num·brae (-brē) 1. A partial shadow, as in an eclipse, between regions of complete shadow and complete illumination.2. The diffuse outer part of a sunspot.3. 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.).4. An outlying surrounding region; a periphery: "Downtown Chicago and its penumbra also stand rejuvenated" (John McCormick).
[New Latin pēnumbra : Latin paene, almost + Latin umbra, shadow.]
pe·num′bral, pe·num′brous adj.
Thesaurus
Adj.1.penumbral - of or pertaining to the region of partial shadow around an umbra