Definition of aurora
1 : dawn
2 capitalized : the Roman goddess of dawn — compare eos
3 : a luminous phenomenon that consists of streamers or arches of light appearing in the upper atmosphere of a planet's magnetic polar regions and is caused by the emission of light from atoms excited by electrons accelerated along the planet's magnetic field lines
auroralplay \-əl\ adjective
auroreanplay \-ē-ən\ adjective
Examples of aurora in a Sentence
a gorgeous pink aurora aroused us out of our slumber
Recent Examples of aurora from the Web
The launch tested a new system that helps studies of the ionosphere and aurora.
The rocket launch will support deeper studies of the ionosphere — a zone of the Earth's outer atmosphere — and aurora, NASA said.
Meanwhile, the aurora borealis could be seen as far south as Texas and Florida and — being 1989 — people worried that nuclear war had begun.
When that happens, solar radiation heats the upper atmosphere and charges it with electricity, which is what causes auroras at the northern and southern poles.
AURORA: A 3:30 a.m. hit-and-run crash in a construction zone on I-5 northbound near the Aurora exit has all but one lane blocked as of 6:30 a.m. for an investigation.
The 670-pound rocket is on a fact-finding mission to support studies of the ionosphere and aurora, but its purpose is overshadowed here on Earth by 10 Pepsi-can-sized canisters.
Earth is protected from the solar wind by its magnetic field; however some particles manage to enter the atmosphere, producing geomagnetic storms and auroras such as the northern lights.
Its other objectives include mapping Jupiter's gravitational and magnetic fields, observing auroras, measuring the amount of water and ammonia in its atmosphere and finding evidence of a solid core.
These example sentences are selected automatically from various online news sources to reflect current usage of the word 'aurora'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
Definition of Aurora
1 city in north central Colorado east of Denver population 325,078
2 city west of Chicago in northeastern Illinois population 197,899
3 town north of Toronto in southeastern Ontario, Canada population 53,203
AURORA Defined for English Language Learners
Definition of Aurora for English Language Learners
: U.S. city, Colorado
: U.S. city, Illinois
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