3. Aurora (l.c.) a radiant emission from the upper atmosphere that occurs as luminous streamers, bands, etc., caused when air molecules are excited by charged particles from the solar wind.
4. Aurora a city in central Colorado, near Denver. 252,341.
5. Aurora a city in NE Illinois. 116,405.
Etymology: (1350–1400; ME < L: dawn, east)
Definition of 'Aurora'
Princeton's WordNet
1. (noun)dawn, dawning, morning, aurora, first light, daybreak, break of day, break of the day, dayspring, sunrise, sunup, cockcrow the first light of day "we got up before dawn"; "they talked until morning"
2. (noun)aurora an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force
3. (noun)Aurora (Roman mythology) goddess of the dawn; counterpart of Greek Eos
Definition of 'Aurora'
Webster Dictionary
1. (noun)Aurora the rising light of the morning; the dawn of day; the redness of the sky just before the sun rises
2. (noun)Aurora the rise, dawn, or beginning
3. (noun)Aurora the Roman personification of the dawn of day; the goddess of the morning. The poets represented her a rising out of the ocean, in a chariot, with rosy fingers dropping gentle dew
4. (noun)Aurora a species of crowfoot
5. (noun)Aurora the aurora borealis or aurora australis (northern or southern lights)
Definitions of 'Aurora'
The Nuttall Encyclopedia
1. Aurora a city in Illinois, U.S., 35 m. SW. of Chicago, said to have been the first town to light the streets with electricity.
Definition of 'Aurora'
The Standard Electrical Dictionary
1. Aurora A luminous display seen in the northern heavens in the northern hemisphere, where it is the Aurora Borealis, and seen in the southern heavens in the southern hemisphere, where it is called Aurora Australis, or indifferently for either, the AuroraPolaris. It takes the form of pale luminous bands, rays and curtains varying in color. Near the poles they are very numerous. A French commission observed 150 auroras in 200 days. Their height is variously estimated at from 90 to 460 miles; they are most frequent at the equinoxes and least so at the solstices. There is a secular variation also, they attain a maximum of occurrence every 11 years together with sun spots, with a minimum 5 or 6 years after the maximum. There is also a period of 60 years, coincident with disturbances in the earth's magnetism. Various attempts have been made to account for them. They have a constant direction of arc with reference to the magnetic meridian (q. v.) and act upon the magnetic needle; in high latitudes they affecttelegraph circuits violently. There is a strong probability that they represent electric currents or discharges. De la Rive considers them due to electric discharges between the earth and atmosphere, which electricities are separated by the action of the sun in equatorial regions. According to Balfour Stewart, auroras and earth currents.(q. v.) may be regarded as secondary currents due to small but rapid changes in the earth's magnetism. The subject is very obscure. Stewart treats the earth as representing the magnetic core of an induction coil, the lower air is the dielectric, and the upper rarefied and therefore conducting atmosphere is the secondary coil. This makes the aurora a phenomenon of induced currents. Then the sun may be regarded as the instigator of the primary changes in the earth's lines of force representing the primary of an induction coil.
[Transcriber's note: Solar wind, streams of electrons and protons, interacting with the earth's magnetic field causes aurora. Neither electrons (1897) nor protons (1920) were known in 1892. The SovietsatelliteLunafirst measured the solar wind in 1959. Eventoday increased understanding of solar and auroral phenomenon continues.]
Definitions of Aurora 
