Dictionary
Thesaurus
Encyclopedia
Translator
Web
Popular Searches
Synonyms
Nearby Words
Definition of penumbrae - 5 dictionary results
Penumbrae at Amazon.com
Buy penumbrae at Amazon! Order by Dec 18- Get it by Xmas
Amazon.com

pe⋅num⋅bra

  [pi-nuhm-bruh]
Use penumbrae in a Sentence
–noun, plural -brae  [-bree] , -bras.
1. Astronomy.
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. Compare umbra (def. 3a).
b. the grayish marginal portion of a sunspot. Compare umbra (def. 3b).
2. a shadowy, indefinite, or marginal area.
Origin:
1660–70; < NL, equiv. to L paen- pen- + umbra shade

Related forms:
pe⋅num⋅bral, pe⋅num⋅brous, adjective
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source Link To penumbrae
Penumbrae at Amazon.com
Buy penumbrae at Amazon! Order by Dec 18- Get it by Xmas
Amazon.com
pe·num·bra   (pĭ-nŭm'brə)   
n.   pl. pe·num·brae (-brē) or pe·num·bras

  1. A partial shadow, as in an eclipse, between regions of complete shadow and complete illumination. See Synonyms at shade.

  2. The grayish 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.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Legal Dictionary

Main Entry: pe·num·bra
Pronunciation: pi-'n&m-br&
Function: noun
Inflected Form: plural -bras
1 : an area within which distinction or resolution is difficult or uncertain penumbra>
2 : an extension of protection, reach, application, or consideration; especially : a body of rights held to be guaranteed by implication from other rights explicitly enumerated in the U.S. Constitution penumbra where privacy is protected from governmental intrusion —Griswold v. Connecticut, 381 U.S. 479 (1965)> —see also Griswold v. Connecticut in the IMPORTANT CASES section —pe·num·bral /-br&l/ adjective
Merriam-Webster's Dictionary of Law, © 1996 Merriam-Webster, Inc.
Cite This Source
Medical Dictionary

Main Entry: pe·num·bra
Pronunciation: p&-'n&m-br&
Function: noun
Inflected Form: plural pe·num·brae /-(")brE, -"brI/ or pe·num·bras
: a blurred area in a radiograph at the edge of an anatomical structure —pe·num·bral /-br&l/ adjective
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
Cite This Source
Science Dictionary
penumbra   (pĭ-nŭm'brə)  Pronunciation Key 
Plural penumbras or penumbrae (pĭ-nŭm'brē)

  1. A partial shadow between regions of full shadow (the umbra) and full illumination, especially as cast by Earth, the Moon, or another body during an eclipse. During a partial lunar eclipse, a portion of the Moon's disk remains within the penumbra of Earth's shadow while the rest is darkened by the umbra. See Note at eclipse.

  2. The grayish outer part of a sunspot. Compare umbra.


The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source
Search another word or see penumbrae on Thesaurus | Reference
FacebookTwitterFollow us:
Partner Sites:
Ask AnswersEviteExpediaHotelsHotwireLife123LiveDailyMy Way