- a shadowy, indefinite, or marginal area.
Origin of penumbra
Examples from the Web for penumbra
In person, Waltz is equally charming, but without the penumbra of menace that comes with having Nazi goons just outside the door.Tarantino's Glorious Nazi
August 16, 2009
This is the entrance into the “penumbra” (or “Partial shade”).The Story of Eclipses
The idea of change is there, I am willing to grant, but it is hidden in the penumbra.Creative Evolution
The penumbra will last quite a long time yet, but it will gradually get fainter and fainter.Pharaoh's Broker
Two tears, phosphorescent in the penumbra, rolled from the eyes of the painter.A Chambermaid's Diary
Each spot is quite sharply divided into an umbra and a penumbra.Astronomy for Young Folks
Isabel Martin Lewis
- a fringe region of half shadow resulting from the partial obstruction of light by an opaque object
- astronomy the lighter and outer region of a sunspot
- painting the point or area in which light and shade blend
Word Origin and History for penumbra
1660s, from Modern Latin penumbra "partial shadow outside the complete shadow of an eclipse," coined 1604 by Kepler from Latin pæne "almost" + umbra "shadow" (see umbrage). Related: Penumbral.
- A partial shadow between regions of full shadow (the umbra) and full illumination, especially as cast by Earth, the Moon, or another body during an eclipse. During a partial lunar eclipse, a portion of the Moon's disk remains within the penumbra of Earth's shadow while the rest is darkened by the umbra. See Note at eclipse.
- The grayish outer part of a sunspot. Compare umbra.