The word 至于 is formed through the conceptual blending of two classical Chinese characters: 至, which carries the core meaning of "to arrive at" or "to reach" a point or extreme, and 于, a classical preposition that denotes direction, location, or relation ("to", "at", "in regard to"). Their combination literally paints the idea of "arriving at" a specific subject or matter. This evolved from indicating a physical or situational endpoint to marking a figurative transition in conversation, shifting the focus "as for" or "when it comes to" a new, often distinct, topic introduced from a prior point of discussion.