Umbra

//ˈʌmbɹə// noun

noun ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    The fully shaded inner region of a shadow cast by an opaque object.
  2. 2
    a region of complete shadow resulting from total obstruction of light wordnet
  3. 3
    The fully shaded inner region of a shadow cast by an opaque object.; The area on the earth or moon experiencing the total phase of an eclipse.
  4. 4
    The central region of a sunspot.
  5. 5
    A shadow. literary
Show 4 more definitions
  1. 6
    An uninvited guest brought along by one who was invited. archaic
  2. 7
    One of the family Umbridae of mudminnows.
  3. 8
    One of genus Umbrina of drums (family Sciaenidae).
  4. 9
    An element of the umbral calculus.

    "In order to set up such an algorithm, we need the notion of multiplicative inverse of an umbra. Two umbrae are said to be multiplicative inverse to each other when αγ ≡ u."

Synonyms

All synonyms
penumbraadumbrationantumbraapparitiondark shadeeidolon

Example

More examples

"A total solar eclipse, or a complete blocking out of the Sun's light, can only be seen by those who live in the area covered by the umbra. People who live in the area of the Earth covered by the penumbra will see a partial eclipse."

Etymology

Borrowed from Latin umbra (“shadow”). Doublet of umber.

Related phrases

Bernoulli umbraumbra rectaumbra versatotal phase

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.