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penumbral

[ pi-nuhm-bruhl ]
/ pɪˈnʌm brəl /
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adjective
Astronomy.
  1. of, causing, or being the partial shadow outside the complete shadow of an opaque body, such as a planet, where the light from the source of illumination is only partly cut off:Four consecutive total lunar eclipses in a row, without any penumbral eclipses in between, are known as a tetrad.Compare umbral 2a.
  2. relating to or being the grayish marginal portion of a sunspot:An average eye can see a sunspot with a penumbral diameter of at least 41 arcseconds.Compare umbral 2b.
relating to or being a shadowy, indefinite, or marginal area:The apple trees provide penumbral lighting that is perfect for studying, thinking, or even a nap.While the beneficiaries of corruption fête themselves with cocktail nights and caviar dreams, its victims wander a penumbral existence.
U.S. Law. of or relating to the set of rights implicit in the U.S. Constitution or Bill of Rights:The wealthy, like everyone else, are entitled to the full enjoyment of the Constitution's express and penumbral guarantees.
QUIZ
SHALL WE PLAY A "SHALL" VS. "SHOULD" CHALLENGE?
Should you take this quiz on “shall” versus “should”? It should prove to be a quick challenge!
Question 1 of 6
Which form is used to state an obligation or duty someone has?
Sometimes pe·num·brous [pi-nuhm-bruhs] /pɪˈnʌm brəs/ .

Origin of penumbral

Words nearby penumbral

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

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