The word 盛大 is formed through the combination of two characters, each contributing a layer of meaning to create a unified concept. 盛 (shèng) pictorially and conceptually carries the sense of a vessel filled to overflowing, conveying flourishing, abundance, and vigorous intensity. 大 (dà), a simple pictograph of a large person, directly represents greatness in scale or grandeur. When fused, 盛大 does not merely mean "big"; instead, 盛 imbues 大 with a qualitative richness, forming the concept of "grandeur" characterized by magnificent scale, lavish fullness, and splendid ceremony, like a festival that is both enormous in size and vibrant in its prosperous atmosphere.