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.
The central dark portion, or nucleus, of a sun spot.
The fainter part of a sun spot; -- now more commonly called penumbra.
Any one of several species of sciaenoid food fishes of the genus Umbrina, especially the Mediterranean species (U. cirrhosa), which is highly esteemed as a market fish; -- called also ombre, and umbrine.
Umbra tree Bot., a tree (Phytolacca diocia) 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).
© Webster 1913.