A D-meson is a type of subatomic particle that contains a charm quark and an anti-up or anti-down quark. It is part of the broader family of mesons, which are made up of a quark and an antiquark. D-mesons come in different varieties, including the D^0, D^+, and D_s^+, each differing in their specific quark composition. D-mesons play a significant role in the study of particle physics and quantum chromodynamics, helping scientists understand the interactions between quarks and the forces that govern them. They are produced in high-energy collisions, such as those occurring in particle accelerators like the Large Hadron Collider.