The word 出于 is formed by combining two distinct characters: 出, which conveys the core idea of "emerging" or "coming out", and 于, a classical preposition that fundamentally denotes "from" or "in". Their fusion creates a single conceptual unit where the sense of emergence (出) is intrinsically linked to a point of origin or motive (于), yielding the combined meaning of "to stem from" or "to be out of".