The word "之间" is formed through the combination of two distinct characters to create an abstract relational concept. The first character, "之", is an ancient grammatical particle that functions as a possessive or linking marker, akin to "of" or "'s", establishing a relationship between two terms. The second character, "间", originally depicted a gap or interval seen through a door under moonlight, concretely representing a physical space or gap between objects. When fused, "之" links the entities, and "间" provides the spatial metaphor, thus forming a single unit that conceptually denotes the intervening space or relational gap "between" any two referenced points, whether physical, temporal, or abstract.