planetesimal

(astronomy) Any of many small, solid astronomical objects that orbit a star and form protoplanets through mutual gravitational attraction.

Japanese Meaning

恒星の周囲を回る多数の小型で固体の天体。これらは互いの重力作用により集まり、原始惑星を形成する候補となる物体。

During the early stages of the solar system, a planetesimal accreted dust and ice until it became a protoplanet.

太陽系の初期段階で、微惑星が塵や氷を集めて成長し、最終的に原始惑星になった。

Sense（1）

(astronomy) Any of many small, solid astronomical objects that orbit a star and form protoplanets through mutual gravitational attraction.

planetesimals

（ plural ）