1. The abundance of heavy elements (metals) in a star or other astronomical object, typically measured relative to hydrogen and helium.
Usage: astronomy; astrophysics

Examples

• The metallicity of the Sun is used as a reference point for comparing other stars.
• Astronomers measure metallicity to understand the age and origin of stars.
• Low-metallicity stars are often found in the outer regions of galaxies.
• The metallicity of a star affects its color and brightness.
• Ancient stars typically have lower metallicity than younger stars.