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- DictionaryPe·num·bra/pəˈnəmbrə/
noun
- 1. the partially shaded outer region of the shadow cast by an opaque object.
1. a. : a space of partial illumination (as in an eclipse) between the perfect shadow on all sides and the full light. b. : a shaded region surrounding the dark central portion of a sunspot. 2. : a surrounding or adjoining region in which something exists in a lesser degree : fringe.
Penumbra definition: the partial or imperfect shadow outside the complete shadow of an opaque body, as a planet, where the light from the source of illumination is only partly cut off.. See examples of PENUMBRA used in a sentence.
In a lunar eclipse, the edge of the earth's shadow — the part that isn't fully dark — is its penumbra. Sun spots also have a penumbra, the outer edge that's not quite as dark as the center. The word comes from the Latin root umbra , which means "shadow."
PENUMBRA definition: 1. a part of a shadow in which only some of the light is blocked, used especially about a shadow…. Learn more.
PENUMBRA meaning: 1. a part of a shadow in which only some of the light is blocked, used especially about a shadow…. Learn more.
Definition of penumbra noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.
a. the partial or imperfect shadow outside the complete shadow of an opaque body, as a planet, where the light from the source of illumination is only partly cut off. b. the grayish marginal portion of a sunspot. 2. a shadowy, indefinite, or marginal area.
