penumbra
/pəˈnʌm.bɹə/ noun
Forms penumbras penumbrae penumbræ pænumbra
- noun A partially shaded area around the edges of a shadow, especially an eclipse.
- noun (astronomy) A region around the edge of a sunspot, darker than the sun's surface but lighter than the middle of the sunspot.
- noun (figuratively) An area of uncertainty or intermediacy between two mutually exclusive states or categories.
- noun (figuratively) An area that lies on the edge of something; a fringe.
- noun Something related to, connected to, and implied by, the existence of something else that is necessary for the second thing to be full and complete in its essential aspects.
- noun (medicine, preceded by "ischaemic", after a stroke) A region of the brain that has lost only some of its blood supply, and retains structural integrity but has lost function.
Synonyms
Etymology
From New Latin pēnumbra, from Latin paene (“almost”) + umbra (“shadow”).
Webster’s 1913
- noun An incomplete or partial shadow.
- noun The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light. Sir I. Newton.
Etymology [NL., fr. L. paene almost + umbra shade.]
Sources: Wiktionary · Webster’s 1913 — from the Wiktionary entry “penumbra”, CC BY-SA 4.0. Details