protoplanet

noun pro·to·plan·et \ ˈprō-tō-ˌpla-nət \
Updated on: 10 Dec 2017

Definition of protoplanet

: 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

protoplanetary

play \ˌprō-tō-ˈpla-nə-ˌter-ē\ adjective

Recent Examples of protoplanet from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'protoplanet.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of protoplanet

1949


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