‘当时’ (dāng shí) literally combines ‘当’ (dāng), meaning ‘at’ or ‘during’, and ‘时’ (shí), meaning ‘time’. Together, they form an adverb meaning ‘at that time’ or ‘then’, referring to a specific moment or period previously mentioned or understood from context. It functions like an English temporal adverb and typically appears at the beginning or middle of a sentence to anchor the action in the past.

This word is neutral in register and widely used in both spoken and written Chinese — especially in narratives, personal stories, historical accounts, or explanations involving sequence of events. Unlike standalone time nouns (e.g., ‘那时’), ‘当时’ emphasizes immediacy and relevance to the preceding context; it often implies contrast, consequence, or vivid recollection. It never refers to future time and cannot stand alone as a noun without modification (e.g., ‘当时的情况’).