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Vulcan, in astronomy

(Encyclopedia)Vulcan, in astronomy, hypothetical planet whose existence was proposed by Le Verrier to explain part of the advance of the perihelion of Mercury, not all of which could be accounted for by gravitation...

Uranus , in astronomy

(Encyclopedia)Uranus yo͝orāˈnəs, yo͝orˈə– [key], in astronomy, 7th planet from the sun, at a mean distance of 1.78 billion mi (2.87 billion km), with an orbit lying between those of Saturn and Neptune; its...

valence, in chemistry

(Encyclopedia)valence, combining capacity of an atom expressed as the number of single bonds the atom can form or the number of electrons an element gives up or accepts when reacting to form a compound. Atoms are c...

Weissenburg in Bayern

(Encyclopedia)Weissenburg in Bayern vīˈsənbo͝ork ĭn bīˈyərn [key] or Weissenburg, town, Bavaria, S Germany. It is a manufacturing center of Middle Franconia; products include gold and silver lace, processed...

rust, in botany

(Encyclopedia)rust, in botany, name for various parasitic fungi of the order Uredinales and for the diseases of plants that they cause. Rusts form reddish patches of spores on the host plant. About 7,000 species ar...

rye, in botany

(Encyclopedia)rye, cereal grain of the family Poaceae (grass family). The grain, Secale cereale, is important chiefly in Central and N Europe. It seems to have been domesticated later than wheat and other staple gr...

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