[ uhm-bruhl ]
See synonyms for umbral on
  1. of or like a shadow or shadowy apparition:Smoke was rising and beginning to coat the clouds a deep, umbral black.In an instant the vampire’s corporeal form dematerialized into an umbral form that quickly merged with the surrounding cover of night.

  2. Astronomy.

    • relating to or being the complete shadow of an opaque body, such as a planet, where all direct light from the source of illumination is cut off:It was to be a very deep eclipse, with the moon passing very close to the center of Earth's umbral shadow.: Compare penumbral 1a.

    • relating to or being the dark central portion of a sunspot:Umbral flashes—powerful brightenings that shock the darkest part of the sunspot—appear continuously every 2 to 3 minutes.: Compare penumbral 1b.

Origin of umbral


Words Nearby umbral Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

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