Lexic.us

Definition of Penumbra

1. Noun. A fringe region of partial shadow around an umbra.

Definition of Penumbra

1. n. An incomplete or partial shadow.

Definition of Penumbra

1. Noun. A partially shaded area around the edges of a shadow, especially an eclipse. ¹

2. Noun. A region around the edge of a sunspot, darker than the sun's surface but lighter than the middle of the sunspot. ¹

3. Noun. Something related to, connected to, and implied by, the existence of something else that is necessary for the second thing to be full and complete in its essential aspects. ¹

4. Noun. (medicine) ''(in "ischaemic penumbra", after a stroke)'' A region of the brain that has lost only some of its blood supply, and retains structural integrity but has lost function. ¹

¹ Source: wiktionary.com

Definition of Penumbra

1. a partial shadow [n -BRAE or -BRAS]

Medical Definition of Penumbra

1. 1. An incomplete or partial shadow. 2. The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light. The faint shade surrounding the dark central portion of a solar spot is also called the penumbra, and sometimes umbra. 3. The part of a picture where the shade imperceptibly blends with the light. Origin: NL, fr. L. Paene almost + umbra shade. Source: Websters Dictionary (01 Mar 1998)

Lexicographical Neighbors of Penumbra

Literary usage of Penumbra

Below you will find example usage of this term as found in modern and/or classical literature:

1. The Sun by Amédée Guillemin (1875)
"Willow-leaves,' their Disposition near a Spot and inside the penumbra. When the disc of the Sun is examined with a moderately powerful glass, ..."

2. Report of the Annual Meeting (1894)
"On Wilton's Theory respecting ike asserted foreshortening of the inner side of the penumbra: of the Solar Spots when near the Sun's Limb, ..."

3. Encyclopædia Britannica: Or, A Dictionary of Arts, Sciences, and by Colin MacFarquhar, George Gleig (1797)
"ОРТ* I С S. The breadth of the external penumbra ... and after that by a narrower penumbra; next to which was a light ..."

4. An Introduction to the True Astronomy: Or, Astronomical Lectures, Read in by John Keill (1739)
"Of the penumbra and its Cone; the Height of the Shadow, and the apparent ... and is called a penumbra ; for tho' all the Sap's Body does not illuminate it, ..."

5. A Dictionary of Science, Literature, & Art: Comprising the Definitions and by George William Cox (1866)
"In solar eclipses those parts of the earth which are covered by the penumbra of the moon are only partially deprived of the sun's light. Let E be the moon, ..."

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