- one of the relatively dark patches that appear periodically on the surface of the sun and affect terrestrial magnetism and certain other terrestrial phenomena.
Origin of sunspot
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for sunspot
And Bishop, Colossus, Warpath, Blink, Sunspot, Quiksilver, Stryker and Havoc will all be there too.
A sunspot is a region on the Sun that is cooler than its surroundings.
Also the present sunspot cycle started its rise to maximum about 1954.
Because the average period of solar rotation in the sunspot zone is not twenty-seven days but twenty-seven point three days.
They are connected in this way: that sunspot activity and S-Region activity certainly go together.
Sunspot activity continues at a high level and is steadily mounting in violence.
- any of the dark cool patches, with a diameter of up to several thousand kilometres, that appear on the surface of the sun and last about a week. They occur in approximately 11-year cycles and possess a strong magnetic field
- informal a sunny holiday resort
- Australian a small cancerous spot produced by overexposure to the sun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for sunspot
Online Etymology Dictionary, © 2010 Douglas Harper
- Any of the dark, irregular spots that usually appear in groups on the surface of the Sun (its photosphere), lasting from a few days to several weeks or more. Sunspots appear dark because they are cooler, by up to 1,500°K, than the surrounding photosphere. They are associated with strong magnetic fields and solar magnetic storms moving in a vortex pattern, similar to a tornado on Earth. The number of sunspots waxes and wanes over an 11-year period; at maximum activity there are often increased numbers of solar flares.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.