sunspot

American  

[suhn-spot] / ˈsʌnˌspɒt /

noun

1. one of the relatively dark patches that appear periodically on the surface of the sun and affect terrestrial magnetism and certain other terrestrial phenomena.

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sunspot British  

/ ˈsʌnˌspɒt /

noun

1. 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

2. informal a sunny holiday resort

3. a small cancerous spot produced by overexposure to the sun

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sunspot Scientific  

/ sŭn′spŏt′ /

1. 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.

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Other Word Forms

• sunspottedness
  noun
• sunspotted
  adjective

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Etymology

Origin of sunspot

First recorded in 1805–15; sun + spot

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Example Sentences

See Examples For:

sunspot

Dr Bloomer says "significant sunspot activity" is visible with solar filtering but that you need magnification when viewing with the naked eye.

From BBC ● Aug. 13, 2026

The newly identified switch-off point also occurs when active sunspot regions move below about 15 degrees solar latitude.

From Science Daily ● Jul. 21, 2026

“Broadly speaking, though, we do know that activity and sunspot numbers should increase in this part of the cycle,” Tom Morgan, a meteorologist for the Met Office, said.

From New York Times ● May 18, 2024

On Wednesday morning, astronomers noted a series of solar flares and coronal mass ejections — essentially, giant explosions of energy — emanating from a massive sunspot more than 15 times the diameter of Earth.

From Los Angeles Times ● May 10, 2024

Sitting cross-legged on the carpet, in a sunspot bright as the open sea, Uhmma unfurled her fingers.

From "A Step from Heaven" by An Na

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