penumbral

American  

[pi-nuhm-bruhl] / pɪˈnʌm brəl /

Sometimes penumbrous

adjective

1. 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.

   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.

2. 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.

3. 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.

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Etymology

Origin of penumbral

penumbra ( def. ) + -al ¹ ( def. )

Example Sentences

When the moon sits in that lighter shadow, it creates a penumbral eclipse, which dims the moon ever so slightly.

From Slate • Apr. 5, 2024

The penumbral environment sparked eager word of mouth that brought a steady stream of slack-jawed visitors during the show’s two-week run.

From Los Angeles Times • Oct. 25, 2023

In what’s known as a penumbral lunar eclipse, the full moon passed within the outer part of Earth’s shadow, causing the moon to dim only slightly.

From Seattle Times • May 5, 2023

Compositionally, this shot of a narrow, penumbral domestic space is a stunner.

From New York Times • Jun. 23, 2022

They sensed somehow that she lived in the penumbral shadows between two worlds, just beyond the grasp of their power.

From "The God of Small Things" by Arundhati Roy