the.com/southern cross

means A small, kite-shaped constellation of five stars (Crux) used in the Southern Hemisphere to roughly locate true south, since there's no bright pole star down there the way Polaris serves the north.

from The name is simply descriptive — Portuguese and Spanish navigators sailing south in the 1400s–1500s, finding themselves in unfamiliar skies with no northern pole star to steer by, noticed this compact cross-shaped cluster near the south celestial pole and started using it for navigation, giving it the plain name 'Cruz' or 'Crux' (Latin for cross). It had long been known to Southern Hemisphere peoples and was even visible to ancient Greek astronomers before precession carried it below the horizon for northern latitudes — so Europeans were really rediscovering, and renaming, something the sky had shown before.