增益 (zēng yì) is a formal noun meaning 'increase' or 'enhancement', especially in contexts involving measurable improvement, benefit, or amplification. The character 增 means 'to increase' or 'to add', while 益 means 'benefit' or 'advantage'; together, they emphasize a positive, often intentional, gain—such as improved performance, added value, or strengthened effect. It is commonly used in technical, medical, and policy-related discourse, rather than casual daily speech.

This word appears frequently in fields like healthcare (e.g., drug efficacy), engineering (e.g., signal amplification), and education (e.g., learning outcomes). Unlike the more general 增加 (zēngjiā, 'to increase' as a verb), 增益 functions almost exclusively as a noun and carries a connotation of qualitative or functional improvement—not just quantitative growth. It often collocates with words like '效果' (effect), '功能' (function), or '能力' (ability), underscoring its association with beneficial advancement.