galaxy

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. 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.
2. n. The Milky Way.
3. n. An assembly of brilliant, glamorous, or distinguished persons or things: a galaxy of theatrical performers.

Century Dictionary and Cyclopedia

1. n. In astronomy, the Milky Way, a luminous band extending around the heavens. It is produced by myriads of stars, into which it is resolved by the telescope. It divides into two great branches, which remain apart for a distance of 150° and then reunite; there are also many smaller branches. At one point it spreads out very widely, exhibiting a fan-like expanse of interlacing branches nearly 20° broad; this terminates abruptly and leaves a kind of gap. At several points are seen dark spots in the midst of some of the brightest portions.
2. n. Hence—2. Any assemblage of splendid, illustrious, or beautiful persons or things.
3. n. Same as galax, 2: a play upon that name.

Wiktionary

1. n. The Milky Way; the apparent band of concentrated stars which appears in the night sky over earth. [from 14th c.]
2. n. Any of the collections of many millions of stars, galactic dust, black holes, etc. existing as independent and coherent systems, of which there are billions in the known universe. [from 19th c.]

GNU Webster's 1913

1. n. The Milky Way, that luminous tract, or belt, which is seen at night stretching across the heavens, and which is composed of innumerable stars, so distant and blended as to be distinguishable only with the telescope.
2. n. A very large collection of stars comparable in size to the Milky Way system, held together by gravitational force and separated from other such star systems by large distances of mostly empty space. Galaxies vary widely in shape and size, the most common nearby galaxies being over 70,000 light years in diameter and separated from each other by even larger distances. The number of stars in one galaxy varies, and may extend into the hundreds of billions.
3. n. A splendid or impressive assemblage of persons or things.

WordNet 3.0

1. n. a splendid assemblage (especially of famous people)
2. n. tufted evergreen perennial herb having spikes of tiny white flowers and glossy green round to heart-shaped leaves that become coppery to maroon or purplish in fall
3. n. (astronomy) a collection of star systems; any of the billions of systems each having many stars and nebulae and dust