倍增 (bèi zēng) is a formal, written verb meaning 'to double, to redouble', often used for abstract growth (knowledge, efficiency). It is more literary than 加倍 (jiā bèi), which is common in both speech and writing and can also mean 'doubly' as an adverb. For concrete numbers (e.g., output, profit), 翻番 (fān fān) is the typical choice.