Any of the relatively cool dark spots appearing periodically in groups on the surface of the sun that are associated with strong magnetic fields. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "sunspot" in a sentence
"Decadal and longer changes in sunspot activity impacting warming and cooling cloud cover patterns are now being recognized as an important factor."
"Officially, the flare-spouting region is called sunspot 1283."
"As a long time fan of contemporary folklore, I thought it might be interesting to track this particular meme, so I used a popular search engine feature in which I registered a particular string (the word sunspot, in this case), and every day it sent me a summary of every new use of this word found on Web sites, in blogs, Usenet newsgroups and newspapers, along with links to these articles."