By A galaxy in space is a massive, gravitationally bound system composed of stars, stellar remnants, interstellar gas, dust, and dark matter, all held together by gravity. Galaxies are the fundamental building blocks of the universe and come in various shapes and sizes.
Galaxies 
Galaxies are immense collections of stars, gas, dust, and dark matter bound together by gravity. They come in diverse shapes and sizes, ranging from spirals like our Milky Way to ellipticals and irregular forms. Galaxies are the fundamental building blocks of the universe, hosting countless stars, planetary systems, and intriguing celestial phenomena. The study of galaxies plays a vital role in our understanding of the cosmos and its evolution.
What Is Our Galaxy Called?
Our galaxy is called the Milky Way. It is a barred spiral galaxy, and it’s the galaxy that contains our solar system. The name “Milky Way” comes from the hazy band of light that stretches across the night sky, which is made up of countless stars, and it resembles a milky appearance.
Galactic 
“Galactic” is an adjective that refers to anything related to galaxies or the Milky Way. It can describe objects, phenomena, or characteristics associated with the vast systems of stars, gas, dust, and dark matter that make up galaxies in the universe. The term “galactic” is often used in astronomy and space sciences to discuss matters pertaining to these cosmic structures.
What Is Space?
Space, in the context of astronomy and physics, refers to the vast, seemingly infinite expanse that exists beyond Earth’s atmosphere. It’s a near-perfect vacuum containing very low matter density, primarily composed of empty space. In space, there is a lack of air, atmosphere, and gravitational forces that we experience on Earth. This environment allows celestial objects like stars, planets, galaxies, and cosmic phenomena to exist and move freely. The study of space, known as astronomy, explores the universe’s mysteries and our place within it.