Metallicity is a term used in astrophysics to describe the abundance of chemical elements that are heavier than helium in a celestial object, such as a star or galaxy. These elements, known as metals in astronomical terms, are created through nuclear fusion in the cores of stars and dispersed into outer space through supernova explosions. Metallicity is an important factor in determining the age, composition, and evolutionary history of stars and galaxies, as well as their ability to form planets and support life. Astronomers use spectroscopic observations to measure metallicity and study its implications for the formation and evolution of celestial objects.