Worldbuilding's meaning is the soul of the setting, the 'why' that makes the 'where' matter. It’s the difference between a map with cool-looking mountains and a map where those mountains were torn from the earth by a sleeping god, and the local miners whisper about the deep, rhythmic sounds they hear. The literal geography is just stage dressing until you imbue it with history, consequence, and thematic weight.
For instance, take the Spice in 'Dune'. Arrakis isn't just a desert planet because it looks harsh. The Spice's existence dictates everything: the feudal political structure, the space-folding technology, the Fremen's entire culture and their relationship with the sandworms. The world's meaning—that a single resource controls the fate of an empire—is the engine for every conflict and character motivation. The setting stops being a backdrop and becomes an active, antagonistic force that shapes the narrative's philosophical questions about power, ecology, and survival.
Conversely, a setting can feel hollow if the worldbuilding lacks a core meaning that connects to the plot. You can have a beautifully described magical academy with floating libraries and talking portraits, but if the magic system has no rules or costs, and the academy's history doesn't impact the students' struggles, it's just an aesthetic. The meaning gives the setting stakes. It tells us what the characters are fighting for, or against, within that space. The crumbling walls of a castle aren't just atmospheric; they're a testament to a fallen dynasty the protagonist is trying to restore, making every stone emotionally charged.