noun
extragalactic nebula
Obsolete term from early 20th-century astronomy, used before galaxies outside the Milky Way were clearly distinguished from nebulae. Replaced by 銀河 (sense 2) or 系外銀河 in modern usage.
See also: 銀河
The term 銀河系外星雲 was once used to refer to objects like the Andromeda Galaxy.