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.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
|Adj.||1.||penumbral – of or pertaining to the region of partial shadow around an umbra|
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.