The word 属于 is formed through the combination of two distinct characters, each contributing its core meaning to create a new, unified concept. The first character, 属, carries the inherent idea of connection, attachment, or categorization under a larger whole. The second, 于, is a classical preposition that fundamentally denotes direction, target, or relationship, essentially pointing "to" or "at" something. Therefore, their combination fuses the notion of "being attached" (属) with the sense of "direction toward a target" (于), resulting in the composite meaning of "to belong to" or "to pertain to", where one entity is directionally and intrinsically connected to another.