(astronomy) A spiral galaxy in the Local Group and closest to the Milky Way, visible to the naked eye in the constellation of Andromeda, the brightest of the Messier objects and often referred to by its designation M31.

(astronomy, galaxies) A cluster of hundreds of galaxies.

(astronomy, galaxies) plural of galaxy cluster

plural of galaxy group

(astronomy) A group of galaxies that hold together gravitationally.

(astronomy) A type of starburst galaxy that primarily emits radiation in the sub-mm/T-hertz range. Due to the extreme dustiness of the galaxy, they are visible mostly in infrared emissions at their redshift, which are subsequently redshifted into the submm/THz range by Hubble expansion.

(Internet slang, often sarcastic) Enigmatic, perplexing, unfathomable; difficult to understand or comprehend.

Alternative form of galaxy-brain

(astronomy) Ellipsis of green pea galaxy.

plural of pea galaxy