Umbral
Encyclopedia
Umbral is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 umbra, meaning "shadow
Shadow
A shadow is an area where direct light from a light source cannot reach due to obstruction by an object. It occupies all of the space behind an opaque object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or reverse projection of the object blocking the...

". It is also the Spanish word for "threshold", and sometimes used as a surname in that language.

Umbral may refer to:
  • Umbral calculus
    Umbral calculus
    In mathematics before the 1970s, the term umbral calculus referred to the surprising similarity between seemingly unrelated polynomial equations and certain shadowy techniques used to 'prove' them. These techniques were introduced by and are sometimes called Blissard's symbolic method...

  • Umbra
    Umbra
    The umbra, penumbra and antumbra are the names given to three distinct parts of a shadow, created by any light source. For a point source only the umbra is cast.These names are most often used to refer to the shadows cast by celestial bodies....

  • Francisco Umbral
    Francisco Umbral
    Francisco Umbral was a Spanish journalist, novelist, biographer and essayist.-Style:...

  • Umbra (World of Darkness)
    Umbra (World of Darkness)
    The Umbra is the spirit world, a shadow or reflection of the real world, in the old World of Darkness role-playing game setting. It is inhabited by spirits, gods, ghosts, and various other supernatural beings....

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