The word "之后" is formed by combining two conceptual building blocks: the character 之, a classical grammatical particle that functions as a linking or possessive marker (like "of" or "'s"), with the character 后, which means "after" or "behind". When fused, the construction literally reads as "the 'after' of [something]", creating a single, fixed unit that expresses the abstract idea of "the time or space following a specific reference point". It is a straightforward semantic fusion where "之" nominalizes and links the concept of "后" to an implied prior event or object, resulting in the meaning "after that" or "following".