Umbra

from WordNet (r) 3.0 (2006)
umbra
    n 1: a region of complete shadow resulting from total
         obstruction of light
    
from The Collaborative International Dictionary of English v.0.48
Ombre \Om"bre\, n. [F., of uncertain origin.] (Zool.)
   A large Mediterranean food fish ({Umbrina cirrhosa}): --
   called also {umbra}, and {umbrine}.
   [1913 Webster]
    
from The Collaborative International Dictionary of English v.0.48
Penumbra \Pe*num"bra\, n. [NL., fr. L. paene almost + umbra
   shade.]
   1. An incomplete or partial shadow.
      [1913 Webster]

   2. (Astron.) The shadow cast, in an eclipse, where the light
      is partly, but not wholly, cut off by the intervening
      body; the space of partial illumination between the umbra,
      or perfect shadow, on all sides, and the full light. --Sir
      I. Newton.
      [1913 Webster]

   Note: The faint shade surrounding the dark central portion of
         a solar spot is also called the {penumbra}, and
         sometimes {umbra}.
         [1913 Webster]

   3. (Paint.) The part of a picture where the shade
      imperceptibly blends with the light.
      [1913 Webster]
    
from The Collaborative International Dictionary of English v.0.48
Umbra \Um"bra\, n.; pl. {Umbrae}. [L., a shadow.]
   1. (Astron.)
      (a) The conical shadow projected from a planet or
          satellite, on the side opposite to the sun, within
          which a spectator could see no portion of the sun's
          disk; -- used in contradistinction from penumbra. See
          {Penumbra}.
      (b) The central dark portion, or nucleus, of a sun spot.
      (c) The fainter part of a sun spot; -- now more commonly
          called penumbra.
          [1913 Webster]

   2. (Zool.) Any one of several species of sciaenoid food
      fishes of the genus {Umbrina}, especially the
      Mediterranean species ({Umbrina cirrhosa}), which is
      highly esteemed as a market fish; -- called also {ombre},
      and {umbrine}.
      [1913 Webster]

   {Umbra tree} (Bot.), a tree ({Phytolacca dioica}) of the same
      genus as pokeweed. It is native of South America, but is
      now grown in southern Europe. It has large dark leaves,
      and a somber aspect. The juice of its berries is used for
      coloring wine. --J. Smith (Dict. Econ. Plants).
      [1913 Webster]
    
from Moby Thesaurus II by Grady Ward, 1.0
21 Moby Thesaurus words for "umbra":
      adumbration, dark shade, eidolon, ghost, gloom, haunt, mere shadow,
      penumbra, phantasm, phantom, revenant, shade, shadiness, shadow,
      shadows numberless, silhouette, skiagram, skiagraph, spook,
      umbrage, umbrageousness

    

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