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penumbra

penumbra

3 9.9
A partly shaded area at the edge of a shadow between full dark and full light
  • noun
  • /pəˈnʌmbrə/
  • Specialized
translation icon : penumbra
  • During a solar eclipse, the penumbra is the area where only part of the sun is obscured by the moon.
  • penumbra of the shadow

These evoke the penumbras that flutter around Whitman's subjects.

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Examples

  • The brightest star is 4.8-magnitude SAO 76532, Omega Tauri, which will be occulted in the penumbra in eastern North America.

    Academic text (1993)
  • And the surrounding areas, the penumbra, which is where part of the sun is, is covered.

  • The diameter of the penumbra is about twice that of the Earth.

    Academic text (1991)
  • At night the penumbra between light and dark weakens.

  • If the umbra is a total eclipse, the penumbra is a partial one; it is paene, almost a total shadow.

    Academic text (2017)
  • The umbra is surrounded by a penumbra (plural: penumbrae), which is not as dark.

    Academic text (1991)
  • As the moon moves into the penumbra, it creates a partial shadow on the Earth's surface.

  • In an eclipse, the penumbra is the region that experiences a slight dimming of light but is not completely dark.

Synonyms

shadow
vspenumbra
544 1.0

A dark shape on the ground made when something blocks light

is a diffuse outer area with gradual partial shading
shade
vspenumbra
102 1.0

A dark area where sunlight does not reach

is a specific partially shaded outer band between complete darkness and full light

Antonyms

1.0

Brightness from the sun, lamps, or fire that makes things visible

How Dark

umbra
  • Specialized
1 9.9
shade
102 1.0
penumbra
  • Specialized
3 9.9
sunlit
9 1.0

Surface Forms

penumbra singular
penumbras plural

Etymology

The word penumbra comes from the Latin parts paene 'almost' and umbra 'shadow', so it literally means 'almost-shadow'. That's why a penumbra is the soft, partial shadow you see at the edge of a dark shadow, such as the faint shading during an eclipse.