The word 极大 is formed by directly combining two independent, meaningful characters: 极, which carries the core idea of "utmost limit" or "extreme", and 大, which means "big" or "great". Their union is not merely additive but multiplicative, where 极 acts as an intensive prefix that radically amplifies the scale conveyed by 大, transforming the concept from simply "big" into "greatest", "maximum", or "extremely large". This formation visually and conceptually stacks the notion of an ultimate boundary onto the notion of size, creating a single, fused concept of superlative magnitude.