• WordNet 3.6
    • n umbra a region of complete shadow resulting from total obstruction of light
    • ***
Webster's Revised Unabridged Dictionary
  • Interesting fact: The word "umbrella" is derived from the Latin root word "umbra", which means shade or shadow
    • Umbra (Zoöl) Any one of several species of sciænoid 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.
    • Umbra (Astron) The central dark portion, or nucleus, of a sun spot.
    • Umbra (Astron) 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.
    • Umbra (Astron) The fainter part of a sun spot; -- now more commonly called penumbra.
    • ***
Century Dictionary and Cyclopedia
    • n umbra A shadow or shade. Specifically, in astronomy: The total shadow of the earth or moon in an eclipse; the dark cone projected from a planet or satellite on the side opposite to the sun. See penumbra (with cut).
    • n umbra Among the Romans, one who went to a feast merely at the solicitation of one invited: so called because he followed the guest as a shadow.
    • n umbra In algebra, a symbol which, when paired with another, makes the symbol of a quantity. See umbral notation, under umbral.
    • n umbra The only genus of Umbridæ; the mud-minnows. See minnow. 2 , and Umbridæ. There are two species, respectively of Europe and North America, U. krameri and U. limi.
    • n umbra [lowercase] A sciænoid fish, Umbrina cirrosa; the umbrine. See cut under Umbrina.
    • ***
Chambers's Twentieth Century Dictionary
    • n Umbra um′bra a shadow:
    • n Umbra um′bra (astron.) the dark cone projected from a planet or satellite on the side opposite to the sun: an uninvited guest whom an invited one brings with him: one of the Umbridæ, the mud-minnows: a sciænoid fish, the umbrine
    • ***


Webster's Revised Unabridged Dictionary
L., a shadow
Chambers's Twentieth Century Dictionary


In literature:

To him he flies, and bows, and bows again, Then, close as Umbra, joins the dirty train.
"Essay on Man Moral Essays and Satires" by Alexander Pope
There had been a spell upon him; the 'Romani nominis umbra.
"The Roman and the Teuton A Series of Lectures delivered before the University of Cambridge" by Charles Kingsley
Alas, 'pulvis et umbra sumus!
"My Novel, Complete" by Edward Bulwer-Lytton
They looked up into serene spaces, and forgot the umbra of pestilence.
"Dragon's blood" by Henry Milner Rideout
For the "Romani nominis umbra," the shadow of the mighty race whom they had conquered, lay heavy on our forefathers for centuries.
"Scientific Essays and Lectures" by Charles Kingsley
Solus hic est sapiens alii volitant velut umbrae.
"The Anatomy of Melancholy" by Democritus Junior
Hammond is like the Umbra you were reading about the other day in Lord Lytton's "Last Days of Pompeii,"' she said to Mary.
"Phantom Fortune, A Novel" by M. E. Braddon
Cras forsan fies, pulvis et umbra levis, Quid tibi opes prosunt?
"The Mirror of Literature, Amusement, and Instruction" by Various
Pulvis et Umbra, 130.
"Modern English Books of Power" by George Hamlin Fitch
The principal works published by Bruno during his stay in Paris are "Il Candelajo" and "Umbrae Idearum.
"The Heroic Enthusiasts,(1 of 2) (Gli Eroici Furori)" by Giordano Bruno

In poetry:

Frunce su rumor el mar.
Los olivos palidecen.
Cantan las flautas de umbría
y el liso gong de la nieve.
"Preciosa Y El Aire" by Federico Garcia Lorca
Puterea noptii bland insenina-vei
Cu ochii mari si purtatori de pace?
Resai din umbra vremilor incoace
Ca sa te vad venid ... ca 'n vis, asa vii!
"Sonnet 4" by Mihai Eminescu

In news:

A solar eclipse showing the moon's shadow on Earth, including the penumbra (large gray oval) and the umbra (black dot).
Conductor Robert Spano to premiere young composer's 'Umbra' this weekend.
Les Mandelbaum, co-founder and president of Umbra, was presented with a 2012 Governor's Honorary Bachelor Degree in Applied Science from Toronto's Humber College.
Notable deaths in arts, A to M. Umbra 's high design in suburban industrial park: Hume.
Umbra recently announced the winners of the 7th Annual Umbra Pratt Design Competition, with first prize going to Pratt industrial design student Jeff Rubio, whose blog I've been following for the past several months.
Les Mandelbaum and Paul Rowan are marking the 30th anniversary of Umbra , the company they founded with a simple window shade.
TORONTO– Umbra has named Matt Carr as director of design, a newly created position in which he will oversee a global design department based here.
Carr has spent the past seven years with Umbra , becoming one of the company's creative leads in 2006.
Ars Magna Lucis et Umbrae by Athanasius Kircher Rome, 1646.

In science:

We now define an umbra M whose relation to the Hermite polynomials will be described in the next section.
A triple lacunary generating function for Hermite polynomials
The analysis of high-resolution Doppergrams and continuum images of sunspot umbrae by Bharti et al. (2007a) show that the umbral dots are surrounded by downwflows.
Structures in compressible magnetoconvection and the nature of umbral dots
Indeed, case G represents a vertical magnetic field strenght of about 3 kG in physical units, just in the range expected for sunspot umbrae.
Structures in compressible magnetoconvection and the nature of umbral dots
The position of umbra/penumbra and penumbra/quiet sun boundary are taken as 0 and 1, respectively.
The properties of penumbral microjets inclination
In this paper we aim to study the energy balance in a sunspot umbra.
Magneto-acoustic wave energy from numerical simulations of an observed sunspot umbra