The word **低谷** (dīgǔ) is a compound formed by combining two characters: **低** (dī), meaning "low," and **谷** (gǔ), meaning "valley." Literally, it describes a low-lying geographical valley. In its modern and most common usage, this literal meaning is extended metaphorically to signify a "low point," "downturn," or "period of difficulty," effectively picturing a person's life, career, or a situation as being in a sunken, difficult terrain from which one must climb out. Thus, its formation follows the common Chinese linguistic pattern of creating an abstract, idiomatic concept by combining two concrete nouns to evoke a vivid mental image.