The Chinese word **回音** (huíyīn), meaning "echo" or "reply," is a compound word formed by combining two meaningful characters: **回** (huí), which means "to return" or "to circle back," and **音** (yīn), which means "sound" or "voice." Together, they create a logical semantic compound where the meaning of "returning sound" perfectly captures the concept of an echo, or metaphorically, a returned message or answer.