protoplanet
noun
pro·to·plan·et
ˈprō-tō-ˌpla-nət 
: a hypothetical whirling gaseous mass within a giant cloud of gas and dust that rotates around a sun and is believed to give rise to a planet
Examples of protoplanet in a Sentence
Recent Examples on the Web
According to the leading Giant Impact Hypothesis, a Mars-sized protoplanet called Theia delivered the one impact to rule them all.
—
Max Bennett, Discover Magazine, 12 Apr. 2025
The observation of these protoplanets is a remarkable achievement for MagAO-X, which is an adaptive optics system.
—Robert Lea, Space.com, 22 Mar. 2025
Cataclysmic collisions with protoplanets, asteroids and comets are thought to be common during a planet’s formation and for the next tens to hundreds of millions of years thereafter.
—Conor Feehly, Scientific American, 4 Mar. 2025
Another is that, until recently, scientists had a hard time separating the chemical components that appear as light spectra from the disc, the new planet, and nearby objects, including the remnants of the star that produced the dusty disc that eventually becomes a protoplanet.
—Paul Smaglik, Discover Magazine, 18 Dec. 2024
See All Example Sentences for protoplanet
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Max Bennett, Discover Magazine, 12 Apr. 2025
The observation of these protoplanets is a remarkable achievement for MagAO-X, which is an adaptive optics system.
—Robert Lea, Space.com, 22 Mar. 2025
Cataclysmic collisions with protoplanets, asteroids and comets are thought to be common during a planet’s formation and for the next tens to hundreds of millions of years thereafter.
—Conor Feehly, Scientific American, 4 Mar. 2025
Another is that, until recently, scientists had a hard time separating the chemical components that appear as light spectra from the disc, the new planet, and nearby objects, including the remnants of the star that produced the dusty disc that eventually becomes a protoplanet.
—Paul Smaglik, Discover Magazine, 18 Dec. 2024
See All Example Sentences for protoplanet
Cite this Entry
“Protoplanet.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/protoplanet. Accessed 22 Apr. 2025.
Copy CitationKids Definition
protoplanet
noun
pro·to·plan·et
ˈprōt-ō-ˌplan-ət
: a whirling mass of gas that rotates around a star and is believed to become a planet
Love words? Need even more definitions?
Merriam-Webster unabridged
Share