A “light” = phos. From phao (to shine or make visible, especially with rays of light); from the same as phaino (to bring light, cause to appear, shine, become visible or clear). This is light, a source of light, fire, or radiance. This is light with specific reference to what it reveals. It is luminousness whether natural or artificial, abstract or concrete, literal or figurative.
B “world” = kosmos. Perhaps from the base of komizo (to carry, convey, recover); from komeo (to take care of). This is order, the world, the universe, including its inhabitants. Literally, this is something that is ordered so it can refer to all creation. It can also refer to decoration in the sense that something is better ordered and, thus, made more beautiful. This is where “cosmos” and “cosmetics” come from.
C “city” = polis. This is a city or its inhabitants. It is a town of variable size, but one that has walls. This is where “metropolis” and “police” come from.