The word 巨大 is formed through a semantic compounding process where two characters with closely related meanings are combined to reinforce and intensify a single concept. Both 巨 (jù, meaning "huge" or "gigantic") and 大 (dà, meaning "big" or "large") independently convey the idea of great size. By joining them, the word creates a layered, emphatic meaning that is more substantial and impactful than either character alone, resulting in the sense of "gigantic", "enormous", or "immense". This formation mirrors the conceptual stacking of similar ideas to express a heightened degree of the shared quality.