Define is Galaxy?...?

A galaxy is a vast system of stars, gas, dust, and other celestial objects bound together by gravity. It is a fundamental unit of the universe and typically contains billions or even trillions of stars, along with various types of interstellar matter. Galaxies come in different shapes and sizes, ranging from spiral galaxies with distinct arms to elliptical galaxies with a more rounded shape. The Milky Way, the galaxy in which our solar system resides, is just one of billions of galaxies in the observable universe.