noun
Modern astronomical term for a cloud of gas and dust in space.
オリオン星雲は肉眼でも見える。
The Orion Nebula is visible even to the naked eye.
Obsolete astronomical term for a galaxy; now replaced by 銀河. This usage is historical and not used in modern Japanese.
See also: 銀河
かつてはアンドロメダ銀河も星雲と呼ばれていた。
The Andromeda Galaxy was once also called a nebula.