"Metal-poor" refers to stars or celestial objects that contain a lower abundance of elements heavier than hydrogen and helium. In astronomy, these elements are collectively called "metals." Metal-poor stars are often older and can provide insights into the early universe, as they formed when fewer heavy elements were available. These stars are typically found in the Milky Way galaxy's halo or in globular clusters. Studying metal-poor stars helps astronomers understand the processes of stellar evolution and the formation of galaxies, as well as the chemical enrichment of the universe over time.