penumbra

pen·um·bra

noun \pə-ˈnəm-brə\

plural pen·um·brae\-(ˌ)brē, -ˌbrī\ or pen·um·bras

Definition of PENUMBRA

1

a : a space of partial illumination (as in an eclipse) between the perfect shadow on all sides and the full light b : a shaded region surrounding the dark central portion of a sunspot

2

: a surrounding or adjoining region in which something exists in a lesser degree : fringe

3

: a body of rights held to be guaranteed by implication in a civil constitution

4

: something that covers, surrounds, or obscures : shroud <a penumbra of secrecy> <a penumbra of somber dignity has descended over his reputation — James Atlas>

— pen·um·bral \-brəl\ adjective

Examples of PENUMBRA

1. <the lunar eclipse began with a subtle darkening of the lunar surface as it passed within the Earth's penumbra>
2. <a penumbra of despair fell over the doomed city>

Origin of PENUMBRA

New Latin, from Latin paene almost + umbra shadow — more at umbrage

First Known Use: 1666

Related to PENUMBRA

Synonyms: dusk, shade, shadiness, shadow, umbra

Related Words: blackness, dimness, duskiness, gloom, gloominess, murkiness, obscurity, semidarkness, somberness; cloudiness

Near Antonyms: brightness, brilliance, effulgence, illumination, incandescence, light, lightness, lucidity, lucidness, luminance, luminosity, luminousness, radiance, radiancy

see all synonyms and antonyms

[+]more[-]hide

Other Astronomy Terms

gibbous, nadir, nebulous, retrograde, sidereal, syzygy, wane, wax, zenith