planetesimal

noun

plan·​e·​tes·​i·​mal ˌpla-nə-ˈte-sə-məl 

-zə-məl

: any of numerous small celestial bodies that may have existed at an early stage of the development of the solar system

Examples of planetesimal in a Sentence

Recent Examples on the Web

When the planets formed, smaller objects, named planetesimals, were flung away from the sun due to gravitational interactions and ended up settling on the very edge of the solar system. —Dan Perry, Newsweek, 28 Feb. 2025

The cloud is believed to appear as a shell of planetesimals — a small celestial body or planet — that surrounds the solar system. —Jack Knudson, Discover Magazine, 24 Feb. 2025

Instead, early planetesimals retained their MVEs even during differentiation. —Jack Knudson, Discover Magazine, 5 Feb. 2025

Enrichment of moderately volatile elements in first-generation planetesimals of the inner Solar System World Economic Forum. —Jack Knudson, Discover Magazine, 5 Feb. 2025

Word History

Etymology

planet + -esimal (as in infinitesimal)

First Known Use

1903, in the meaning defined above

Phrases Containing planetesimal

• planetesimal hypothesis

Rhymes for planetesimal

• hexadecimal
• decimal
• infinitesimal

Kids Definition

planetesimal

noun

plan·​e·​tes·​i·​mal ˌplan-ə-ˈtes-ə-məl 

-tez-

: one of numerous small solid heavenly bodies which may have existed at an early stage of the development of the solar system and from which the planets may have been formed