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penumbra

pe·num·bra

 (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.
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.

penumbra

(pɪˈnʌmbrə)
n, pl -brae (-briː) or -bras
1. (Astronomy) a fringe region of half shadow resulting from the partial obstruction of light by an opaque object
2. (Astronomy) astronomy the lighter and outer region of a sunspot
3. (Art Terms) painting the point or area in which light and shade blend
[C17: via New Latin from Latin paene almost + umbra shadow]
peˈnumbral, peˈnumbrous adj
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

pe•num•bra

(pɪˈnʌm brə)

n., pl. -brae (-brē), -bras.
1.
a. the partial or imperfect shadow outside the complete shadow of an opaque body, as a planet, where the light from the source of illumination is only partly cut off.
b. the grayish marginal portion of a sunspot.
2. a shadowy, indefinite, or marginal area.
[1660–70; < New Latin, = Latin paen(e) almost + umbra shade]
pe•num′bral, pe•num′brous, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

pe·num·bra

(pĭ-nŭm′brə)
1. A partial shadow between regions of complete shadow and complete illumination, especially as cast by Earth, or the moon, over another body during an eclipse.
2. The grayish outer part of a sunspot. Compare umbra.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.penumbra - a fringe region of partial shadow around an umbrapenumbra - a fringe region of partial shadow around an umbra
shadow - shade within clear boundaries
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.

penumbra

noun
Comparative darkness that results from the blocking of light rays:
The American Heritage® Roget's Thesaurus. Copyright © 2013, 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Translations

penumbra

[pɪˈnʌmbrə] N (penumbras or penumbrae (pl)) [pɪˈnʌmbriː]penumbra f
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005

penumbra

n pl <-s or -e> → Halbschatten m
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007
References in classic literature ?
penumbrae , and all the magic of chiaro-oscuro , does not exist on the moon.
But when Hujar steps back, as he does in a number of sweeping shots of institutional architecture--corporate high-rises, City Hall, an avenue of nine-teenth-century office buildings--the light seems almost beneficent, emanating in phosphorescent penumbrae from intermittently illuminated windows.