Baryons are a type of subatomic particle made up of three quarks. They are one of the two main categories of particles in the Standard Model of particle physics, the other being mesons. Baryons include well-known particles such as protons and neutrons, which are the building blocks of atomic nuclei. Baryons are classified as fermions, meaning they follow the Pauli exclusion principle, which states that no two identical fermions can occupy the same quantum state simultaneously. This property is crucial for the stability of matter, as it allows baryons to form the diverse range of elements found in the universe.