You searched for: “penumbra
penumbra (s) (noun), penumbrae (pl)
1. In astronomy, a partial outer shadow that is lighter than the darker inner shadow ("umbra"): Penumbra is the area between complete darkness and the complete light in an eclipse.
2. An indistinct area; especially, a situation in which something is unclear or uncertain: In astronomy, a penumbra is a grayish area surrounding the dark center of a sunspot.
3. The outer region or periphery of something: A penumbra area is covered by shadiness, so it is not completely dark.
4. Etymology: from Modern Latin penumbra. "partial shadow outside the complete shadow of an eclipse"; coined in 1604 by Kepler from Latin pæne, "almost" + umbra, "shadow".
This entry is located in the following units: peni-, pen- (page 1) umbra-, umbro-, umbr-, umbel- (page 1)
Word Entries at Get Words: “penumbra
penumbra
1. A grayish area surrounding the dark center of a sunspot.
2. A partial outer shadow that is lighter than the darker inner shadow or umbra; such as, the area between complete darkness and complete light in an eclipse.

An observer within the penumbral region will see a partial eclipse. It is also the name given to the outer dark region of a sunspot.

This entry is located in the following unit: Astronomy and related astronomical terms (page 18)