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“penumbra”
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".
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”
A grayish area surrounding the dark center of a sunspot: A penumbra is the 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)