Penumbra Definition

pĭ-nŭmbrə
penumbrae, penumbras
noun
The partly lighted area surrounding the complete shadow (umbra) of a body, as the moon, during an eclipse.
Webster's New World
The diffuse outer part of a sunspot.
American Heritage
A vague, indefinite, or borderline area.
Webster's New World
The less dark region surrounding the dark central area of a sunspot.
Webster's New World
An area in which something exists to a lesser or uncertain degree.
American Heritage
Synonyms:

Other Word Forms of Penumbra

Noun

Singular:
penumbra
Plural:
penumbrae, penumbras

Origin of Penumbra

  • From New Latin penumbra, from Latin paene (“almost") + umbra (“shadow").

    From Wiktionary

  • New Latin pēnumbra Latin paene almost Latin umbra shadow

    From American Heritage Dictionary of the English Language, 5th Edition

Penumbra Sentence Examples

  • The notions of the penumbra and umbra are important in considering eclipses (q.v.).

  • In the neighbourhood surrounding the penumbra the granules appear to be packed more closely, forming brilliant patches called faculae.

  • It is surrounded by the penumbra that receives some light from the light source.

  • A partial lunar eclipse occurs when the Moon passes into the penumbra, or partial shadow.

  • Group differences in average volume of ischaemic penumbra salvaged will be analyzed by t-test, adjusting for baseline differences in prognostic variables.

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Words Starting With

PPEPEN

Words Ending With

ARABRA

Unscrambles

penumbra

Words Starting With P and Ending With A

Starts With P & Ends With AStarts With PE & Ends With AStarts With P & Ends With RA

Word Length

8 Letter Words8 Letter Words Starting With P8 Letter Words Ending With A