sunspot

[ suhn-spot ]
/ ˈsʌnˌspɒt /
|

noun

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

First recorded in 1805–15; sun + spot
Related formssun·spot·ted, adjectivesun·spot·ted·ness, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sunspot

British Dictionary definitions for sunspot

sunspot

/ (ˈsʌnˌspɒt) /

noun

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
Derived Formssunspotted, adjective
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

sunspot


n.

1868, in astronomy, from sun (n.) + spot (n.). Earlier "a spot on the skin caused by exposure to the sun" (1818).

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for sunspot

sunspot

[ sŭnspŏt′ ]

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.