protoplanet

American  

[proh-toh-plan-it] / ˈproʊ toʊˌplæn ɪt /

noun

Astronomy.

1. the collection of matter, in the process of condensation, from which a planet is formed.

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protoplanet British  

/ ˌprəʊtəʊˈplænɪt /

noun

1. a planet in its early stages of evolution by the process of accretion

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Etymology

Origin of protoplanet

First recorded in 1945–50; proto- + planet

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Example Sentences

See Examples For:

protoplanet

Instead, it was likely a differentiated body with an iron core surrounded by rocky material, similar to a small protoplanet or a differentiated asteroid.

From Science Daily ● Jun. 22, 2026

A giant collision between the young Earth and a smaller protoplanet has long been the prevailing theory for the Moon’s formation.

From Scientific American ● Nov. 2, 2023

Perhaps, the new study suggests, those clumps came from the protoplanet that smashed into Earth, leading to the moon’s formation.

From National Geographic ● Nov. 1, 2023

These rocks helped show, for example, that the moon probably formed after an extremely violent collision between baby Earth and another protoplanet.

From New York Times ● Dec. 14, 2022

If a protoplanet gets to several Earth masses, it can grab a thick envelope of gas and become a gas giant like Jupiter or Saturn.

From Science Magazine ● Apr. 3, 2022

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