翻倍 is a verb meaning 'to double'—specifically, to increase something to exactly twice its original value or quantity. The character 翻 literally means 'to flip' or 'to turn over', suggesting a complete, dramatic change; 倍 means 'multiple' or 'times', as in 'twice' (二倍) or 'ten times' (十倍). Together, 翻倍 emphasizes the sudden or significant nature of doubling—not just any increase, but precisely ×2. It’s commonly used in economic, statistical, and everyday contexts involving numbers: prices, salaries, populations, production, or time estimates.

This word functions as a predicate verb and typically follows the subject directly, often with time phrases (e.g., in one year) or comparative markers like 比 last year. It does not take an object—it describes the change itself—so you say 'the price 翻倍', not 'the price 翻倍 the cost'. While it can be used in both formal reports and casual speech, it carries a neutral-to-formal register and is rarely used for abstract or emotional doubling (e.g., 'double the joy' uses different phrasing).