pho·​to·​sphere ˈfō-tə-ˌsfir How to pronounce photosphere (audio)
: a sphere of light or radiance
: the luminous surface layer of the sun or a star
photospheric adjective

Examples of photosphere in a Sentence

Recent Examples on the Web Four payloads for studying the sun will gaze at the star’s photosphere, its layer visible to us; the chromosphere, a thin layer of plasma on top of the photosphere; and the corona, the outermost layer of the sun that starts about 1,300 miles above the photosphere. Will Sullivan, Smithsonian Magazine, 6 Sep. 2023 Despite their great temperatures, dwarf stars can and do harbor water molecules in their own atmospheres – their photospheres. Matt Hrodey, Discover Magazine, 15 June 2023 The photosphere appears black at these wavelengths, because that region is not nearly hot enough to shine brightly in extreme ultraviolet. Corey S Powell, Discover Magazine, 11 Aug. 2013 That material came from the planet itself, which likely passed through the star’s outer photosphere before falling to its demise. Matt Hrodey, Discover Magazine, 11 May 2023 The plume created shocks and pulsations that triggered an eruption, peeling off a chunk of the star’s outer shell called the photosphere. Ashley Strickland, CNN, 12 Aug. 2022 These Texas-size granules cover nearly the entire photosphere. Brian T. Jacobs, National Geographic, 24 Aug. 2021 The image on the right, acquired at the same time, is a kind of magnetic map of the photosphere. Tom Yulsman, Discover Magazine, 20 Apr. 2014 Like water boiling in a pot, plasma cells, or granules, carry heat to the sun’s glowing and visible surface, the photosphere. Brian T. Jacobs, National Geographic, 24 Aug. 2021 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'photosphere.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


photo- + -sphere; in sense 2 probably as translation of German Lichtatmosphäre

First Known Use

1664, in the meaning defined at sense 1

Time Traveler
The first known use of photosphere was in 1664

Dictionary Entries Near photosphere

Cite this Entry

“Photosphere.” Dictionary, Merriam-Webster, Accessed 23 Sep. 2023.

Kids Definition


pho·​to·​sphere ˈfōt-ə-ˌsfi(ə)r How to pronounce photosphere (audio)
: the shining surface of the sun or a star
photospheric adjective

More from Merriam-Webster on photosphere

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!