The word 由于 is formed through the combination of two characters, each contributing a core conceptual piece: 由, which carries the fundamental notion of "origin", "source", or "to follow from", and 于, a classical grammatical particle that essentially marks a relationship, often of place, time, or cause. Their fusion creates a single unit where 于 acts to grammaticalize and solidify the causal sense inherent in 由, transforming it from a simpler idea of origin into a more abstract and relational compound meaning "owing to" or "because of". Thus, it is a conceptual synthesis where one part provides the substantive meaning and the other provides the relational framework.