Definition of penumbra in English:

penumbra

noun

  • 1The partially shaded outer region of the shadow cast by an opaque object.

    • ‘He brings a sharp eye to the bedside of a poet friend and to urban decay, ‘the dust of voices, / the smoky penumbra around streetlights.’’
    • ‘The penumbra of his face, and the emanations of light leaking from behind his ears, and his hair, was blinding.’
    • ‘He is pacing up and down the library in the gloom, ‘the penumbra of the library’, as he put it, and he thinks of a tiger in the jungle, and this is ‘The Other Tiger’.’
    • ‘The black penumbra which appears when you first look to its edges soon becomes brown.’
    • ‘Long, thin filaments radiate from the umbra into a brighter surrounding region called the penumbra.’
    • ‘Shadows and penumbras were instantaneously formed from the myriad of trees and hills that he surveyed through the window, and just as quickly vanished.’
    • ‘And we would do well to remember that the penumbra is the lighter, outer region of the shadow, the halo, indeed, of the shadow.’
    • ‘A penumbra of fiery purple encircles this near-seamless construction of photographs, objects and painted images on wood.’
    • ‘Neon glow qualifies the relation of work to wall; each piece generates its own set of shadow and penumbra.’
    • ‘In other cases the Moon does not pass through the umbra at all, just going through the penumbra (a region of partial shadow).’
    • ‘He stands within the penumbra of the falls, near the top of Irish Mountain.’
    • ‘The Moon begins to enter the Earth's outer shadow, or penumbra, at 9: 06 P.M.’
    • ‘Our planet's shadow has two parts, a dark inner core called the umbra and a pale outer fringe called the penumbra.’
    1. 1.1Astronomy
      The shadow cast by the earth or moon over an area experiencing a partial eclipse.
      • ‘So, one will observe either a total eclipse by the umbra (which can be well observed), a partial eclipse by the umbra and penumbra, or a total or partial eclipse by the penumbra only.’
      • ‘A penumbral eclipse, sometimes called an appulse, occurs when the Moon misses the Earth's umbra but passes through its penumbra or secondary shadow.’
      • ‘The Moon on April 24th will glide through Earth's penumbra, producing what astronomers call a ‘penumbral lunar eclipse.’’
      • ‘As the partial phase progresses, you are moving deeper and deeper into the Moon's penumbra.’
      • ‘On Friday morning, the moon will enter the penumbra of the Earth's shadow at 3: 05 am, and the moonlight will become dimmer.’
    2. 1.2Astronomy
      The less dark outer part of a sunspot, surrounding the dark core.
      • ‘Theorists suspect that the penumbra is key to keeping a sunspot intact.’

Origin

Mid 17th century: modern Latin, from Latin paene almost + umbra shadow.

Pronunciation:

penumbra

/pəˈnəmbrə/