What is a large cloud of dust and gas in space typically called?

A large cloud of dust and gas in space is typically called a nebula. Nebulae are fundamental components of the universe, often serving as the materials from which new stars and planets form. These clouds are primarily composed of hydrogen, helium, and other ionized gases, along with dust particles.

Nebulae can be categorized into various types, including emission nebulae, absorption (or dark) nebulae, and planetary nebulae, each representing different processes and conditions present in space. They often play a crucial role in the lifecycle of stars, as they can collapse under their own gravity to form new astronomical bodies.

In contrast, a galaxy is a large system that contains stars, star clusters, planetary systems, gas, dust, and dark matter bound together by gravity. A star cluster refers to a group of stars that are physically related, and an exoplanet is a planet that orbits a star outside our solar system. Each of these terms describes different astronomical phenomena, further highlighting the unique classification of a nebula as a significant entity comprised of dust and gas.