The galaxy (Earth-2042)

"This galaxy is vast; its wonders and beauty are almost unfathomable. But the galaxy also hides dark secrets, some of which have lain dormant since the beginning of time itself. There is a danger in secrets, both in seeking and in knowing. Some things are meant to be hidden from view. Some mysteries defy understanding, and sometimes even the things we think we know are untrue. Some secrets should remain untouched."

- Cortana, after finishing her retelling of galactic history.

The galaxy, as it is commonly referred to, is one of the trillions of galaxies in the universe. The galaxy is a vast composite of over 400 billion estimated stars and over 3.2 million habitable systems orbiting around a super-massive black hole at the heart of the galaxy. The galactic arms rotated around this black hole across a diameter of over 100,000 light-years. It is home to countless sentient species and star systems.

The galaxy serve as the setting for trade, politics, and war throughout galactic history. In historical memory, the galaxy would see the successive eras of the Forerunners, the Galactic Republic, Galactic Empire, New Galactic Republic, among others, and was home to the Force-using orders of the Jedi and Sith.

Source

 * https://starwars.fandom.com/wiki/The_galaxy