planetesimal

名词 planetesimal:

1. one of many small solid celestial bodies thought to have existed at an early stage in the development of the solar system

plan.e.tes.i.mal

n.（名词）
Any of innumerable small bodies thought to have orbited the sun during the formation of the planets.
星子：任何数不清的小固体块，被认为曾在行星形成阶段中在围绕太阳的轨道上运行

来源：
planet
planet
(infinit)esimal
(infinit)esimal

【引伸】
plan.etes.imal
adj.（形容词）