Pions are subatomic particles that play a crucial role in the strong nuclear force, which holds atomic nuclei together. They are classified as mesons, meaning they are made up of a quark and an antiquark. Pions come in three varieties: positively charged (π+), negatively charged (π-), and neutral (π0). These particles are relatively light compared to other mesons and have a short lifespan, decaying into other particles within a fraction of a second. Pions are essential in particle physics and are often produced in high-energy collisions, such as those occurring in particle accelerators like the Large Hadron Collider.