Penumbra

From New Latin penumbra, from Latin paene ("almost") + umbra ("shadow").

Full definition of penumbra

(plural penumbras)

2011, Galen C. Duree, Jr., Optics for Dummies, Wiley Publishing, Inc. (2011), ISBN 9781118017234, page 61:The other places see the penumbra of the moon's shadow fall on the earth, so the eclipse is partial, and part of the sun's disc is still visible.
2011, Frank McLynn, Captain Cook: Master of the Seas, Yale University Press (2011), ISBN 9780300114218, page 112:In the boiling temperature of 119 Â° F â€“ the hottest they had experienced so far â€“ they watched as the penumbra of Venus blurred its outline at the precise moment the disc crossed the sun.
2012, Michael A. Seeds & Dana E. Backman, Horizons: Exploring the Universe, Brooks/Cole (2012), ISBN 9781111430207, page 37:The part of the moon that remains in the penumbra receives some direct sunlight, and the glare is usually great enough to prevent your seeing the faint coppery glow of the part of the moon in the umbra.

(astronomy) A region around the edge of a sunspot, darker than the sun's surface but lighter than the middle of the sunspot.
(figuratively) An area of uncertainly or intermediacy between two mutually exclusive states or categories.

1998, Debraj Ray, Development Economics, Princeton University Press (1998), ISBN 0691017069, pages 346-347:These firms or businesses are not illegal in the strict sense, but there is a shadowy penumbra within which they live, and it is often convenient for the government to look the other way.
2010, Denis Farkasfalvy, Inspiration and Interpretation: A Theological Introduction to Sacred Scripture, The Catholic University of America Press (2010), ISBN 9780813217468, page 188:God chose to descend into the realm of human imperfection, where the light of truth is spare and must exist in the penumbra of partial knowledge mixed with partial ignorance.
2011, Bill Schwartz, The White Man's World, Oxford University Press (2011), ISBN 9780199296910, page 136:Unlike some of his contemporaries Parkes never implied that the Irish were close, in the racial hierarchy, to black, condemned to some racial penumbra, between black and white; but nor, given Catholic exclusion from the given traditions of his native radicalism, were the Irish white in the same way that he was.

1975, Bryan R. Wilson, The Noble Savages: The Primitive Origins of Charisma and Its Contemporary Survival, Quantum Books (1975), ISBN 0520028155, page 116:Whilst the orthodox, de-charismatized churches steadily lose influence and support and the new cults develop, in the religious penumbra there have persisted, during the last century, echoes of charisma.
1986, John McCormick, "Chicago Bounces Back", Newsweek, Volume 108, page 42:But for all the expansionist energy of a metro area that sprawls from Wisconsin to Indiana (total population: 7.2 million), downtown Chicago and its penumbra also stand rejuvenated.
2000, Steve Jones, The Language of Genes, Flamingo (2000), ISBN 0006552439, page xv:Some are accounts of the latest advances, but too many are in that weary penumbra of science inhabited by sociologists, who wander like children in a toyshop, playing with devices they scarcely understand.

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.

1965, William O. Douglas, , , 381 U.S. 479The foregoing States Supreme Court cases suggest that specific guarantees in the Bill of Rights have penumbras, formed by emanations from those guarantees that help give them life and substance.

(medicine) (in "ischaemic penumbra", 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.