sunspot

American

[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.

sunspot British

/ 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
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

sunspot Scientific

/ sŭn′spŏt′ /

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.

Other Word Forms

sunspotted adjective
sunspottedness noun

Etymology

Origin of sunspot

First recorded in 1805–15; sun + spot

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Maybe it was something about the rotation of the earth, or sunspots, or something bizarre like that.

From Literature

A solar cycle is the sun's transition from one solar maximum to the next and is measured through the number of visible sunspots on the surface of the sun, the Met Office said.

From BBC

During the peak of the current cycle, which Nasa confirmed occurred in October 2024, a higher number of sunspots led to more frequent eruptions of solar flares and coronal mass ejections.

From BBC

Starspot: A relatively cool, dark region on a star, similar to sunspots on the Sun.

From Science Daily

The Sun's magnetic cycle is a repeating pattern that lasts about 11 years, marked by fluctuations in sunspot numbers and a complete reversal of the Sun's magnetic poles.

From Science Daily

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023