The word 调查 is formed by combining two independent characters, each contributing a core meaning to create a new, composite concept. The first character, 调 (diào), carries notions of adjusting, transferring, or probing into something. The second, 查 (chá), means to examine, inspect, or look into. Their fusion conceptually merges the idea of methodically probing or sifting through with the act of close examination, resulting in the integrated meaning of "to investigate" or "to survey".