(astronomy) A galaxy having a number of arms of younger stars that spiral out from the centre containing older ones

A galaxy having a smooth, featureless light-profile. It is one of the three main classes of galaxies originally described by Edwin Hubble in his 1936 work “The Realm of the Nebulae”.

(astronomy) Type of galaxy that is very luminous at radio wavelengths.

(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) plural of galaxy cluster

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

plural of galaxy group

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

(astronomy) Any of a class of galaxies that have nuclei with excessive amounts of ultraviolet emissions.

Synonym of spiral galaxy