umbra
  • Latin for shadow. Has two main uses among astronomers – for the dark central zone of a sunspot and for the dark centre part of the Earth’s or Moon’s shadow at an eclipse.
  • A dark area, such as that of a shadow, which is blocked from light rays emanating from a given source. Also, the darkest area of such a shadow.
  • A dark area arising from the shadow cast by a celestial body, such as the sun or moon, during an eclipse. Also, the darkest area of such a shadow.

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