Any of numerous large-scale aggregates of stars, gas, and dust that constitute the universe, containing an average of 100 billion (1011) solar masses and ranging in diameter from 1,500 to 300,000 light-years. Also called nebula.
often Galaxy The Milky Way.
An assembly of brilliant, glamorous, or distinguished persons or things: a galaxy of theatrical performers.
[Middle English galaxie, the Milky Way, from Late Latin galaxiās, from Greek, from gala, galakt-, milk; see melg- in Indo-European roots.]
Any of numerous large-scale collections of stars, gas, and dust that make up the visible universe. Galaxies are held together by the gravitational attraction of the material contained within them, and most are organized around a galactic nucleus into elliptical or spiral shapes, with a small percentage of galaxies classed as irregular in shape. A galaxy may range in diameter from some hundreds of light-years for the smallest dwarfs to hundreds of thousands of light-years for the largest ellipticals, and may contain from a few million to several trillion stars. Many galaxies are grouped into clusters, with the clusters themselves often grouped into larger superclusters. See more at active galaxy, See also elliptical galaxy, irregular galaxy, lenticular galaxy, spiral galaxy.