The word 呼吸 is formed through the complementary pairing of two individual characters, each depicting one half of a single, continuous biological action. The first character, 呼, visually and conceptually represents the act of exhaling breath outward. The second, 吸, represents the opposing act of drawing breath inward. By placing them side-by-side, the compound perfectly encapsulates the complete, rhythmic cycle of breathing itself, creating a meaning greater than the sum of its parts through direct semantic juxtaposition.