noun (plural penumbrae /pɪˈnʌmbriː/ or penumbras)
1The partially shaded outer region of the shadow cast by an opaque object.
- In other cases the Moon does not pass through the umbra at all, just going through the penumbra (a region of partial shadow).
- And we would do well to remember that the penumbra is the lighter, outer region of the shadow, the halo, indeed, of the shadow.
- The Moon begins to enter the Earth's outer shadow, or penumbra, at 9: 06 P.M.
1.1 Astronomy The shadow cast by the earth or moon over an area experiencing a partial eclipse.
- On Friday morning, the moon will enter the penumbra of the Earth's shadow at 3: 05 am, and the moonlight will become dimmer.
- 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.
- The Moon on April 24th will glide through Earth's penumbra, producing what astronomers call a ‘penumbral lunar eclipse.’
2A peripheral or indeterminate area or group: an immense penumbra of theory surrounds any observation
More example sentences
- Like many words in everyday use, it carries with it, as it were, a penumbra of different shades of meaning.
- Others tell different jokes that are incoherent except in the penumbra cast by the joke.
- He had a sound belief in astrology, the stars being the twinkling penumbra of his incandescent belief in the ‘free market,’ with whose motions it was blasphemous to tamper.
- Example sentences
- I think it's important that we recognize the existence of this problematic, penumbral group, but that doesn't mean that there aren't people who do take responsibility.
- Rick would howl, and then rapidly half-wade, half-swim down the penumbral corridor and stumble up onto the next sandbank, laughing.
- The nearly flat trail was bordered on one side by precipitous slopes, where penumbral snowfields fell into the crater 100 feet below.
Words that rhyme with penumbraumbra
For editors and proofreaders
Line breaks: pen|um¦bra
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