The word "适应" is formed through the conceptual combination of its two component characters. The first character, "适" (shì), carries the core meaning of "to fit" or "to suit", implying a state of being appropriate or aligned. The second character, "应" (yìng), means "to respond" or "to correspond", introducing an element of active reaction or reciprocal alignment. Their synthesis creates a single concept where the idea of "fitting" (适) is merged with the idea of "responding" (应), resulting in the holistic notion of "adaptation", the dynamic process of adjusting oneself to fit and function within changing conditions.