利息 (lì xī) means 'interest' — specifically the money earned on savings or paid on loans. It combines 利 (lì), meaning 'profit' or 'gain', and 息 (xī), meaning 'interest', 'breath', or 'rest', but here it carries the financial sense of 'return on capital'. Together, they form a compound noun exclusively used in monetary contexts — never for biological, emotional, or abstract 'interest' (like curiosity, which is 兴趣 xìngqù).

This term appears frequently in banking, finance, and everyday discussions about money — for example, when comparing bank deposit rates, calculating loan costs, or reading financial news. It’s always uncountable in Chinese and doesn’t take measure words like 个; instead, it’s quantified with terms like 年利率 (annual interest rate) or 百分之五的利息 (5% interest). Unlike English, 利息 is never used as a verb — you don’t 'interest' something; you 'earn' (赚) or 'pay' (支付) interest.