Astronomy Answers
From the Astronomical Dictionary

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The description of the word you requested from the astronomical dictionary is given below.

the galaxy

'ga‧lax‧y; galaktos = [Greek] milk

A galaxy is a region of space with millions to thousands of millions of stars and many clouds of gas that are tied together by their gravity. A typical spiral galaxy or elliptical galaxy (two types of galaxies) contains 100 thousand million stars, has a diameter of 100,000 lightyears, and is at a distance of a few million lightyears from other neighboring spiral or elliptical galaxies. Our Solar System is part of the Milky Way, which is a fairly ordinary spiral galaxy.