The word **波动 (bōdòng)** is a compound formed by combining two characters: **波 (bō)**, meaning "wave" (as in water or physics), and **动 (dòng)**, meaning "to move" or "movement." Literally, it depicts the image of a wave's motion. In modern usage, this literal meaning extends metaphorically to describe any phenomenon that exhibits irregular rises and falls, such as fluctuations in prices, emotions, or signals, effectively capturing the concept of instability or variability through the conceptual blend of "wave-like movement."