shortening of aurora borealis (q.v.).
Examples from the Web for borealis
Until Hafernik and his late-night discovery, though, no one knew the Apocehalus borealis were zombifying bees.
Above these mountains shone the flaring rays of the borealis.Gods of the North|Robert E. Howard
Was not the Aurora Borealis performing in all its splendour?Shining Ferry|Sir Arthur Thomas Quiller-Couch
"You'd have trouble finding a rhyme to borealis," said the Poet.The Inventions of the Idiot|John Kendrick Bangs
This spider lives in houses, around window frames and similar places, like borealis.The Common Spiders of the United States|James Henry Emerton
Constable Hope, not a little discouraged by the way his report was received, sauntered out and drifted towards the Borealis.The Great Gold Rush|W. H. P. (William Henry Pope) Jarvis