Bob, κόσμος originally meant "order," "good order." It was Pythagoras (closely followed by Heraclitus) who first used it to designate the "order of the universe." Later writers blurred the distinction (if any) between "world order" and "world," though it was the universe, including our little "world," that was always meant. It was especially attractive to use as a word for the universe as we perceive it from here "below" the brilliant day sky and especially the dazzling night sky, since those seemed to fit with a growing use of κόσμος to mean "(orderly) adornment," "decorative perfection."
Γῆ or (to use her full name) Γαῖα was the fruitful and nurturing Goddess who sustains us all as we pass from, over, and back into her body. She is the material of our world. To see mountains, forests, fields of grain, is to look down and around and see Γαῖα. To look up is to see the ethereal order, the κόσμος.