The word 唯一 is formed through the conceptual combination of two characters: 唯, which carries the fundamental idea of "alone" or "solely", originating from a pictograph of a mouth giving an exclusive response, and 一, meaning "one". Their fusion is not merely additive but philosophical, merging the notion of exclusivity (唯) with the absolute, undivided unit (一) to express the abstract idea of "the only one" or "unique", creating a compound where the second character specifies and concretizes the solitary nature implied by the first.