利息
りそく · risoku · JLPT N1 · noun
interest
🏦 利 = profit + 息 = offspring: profit that breeds more money
息 also means offspring, as in 子息. Bank interest is money that breeds: savings give birth to new money over time.
利 — grain 禾 + knife 刂
Originally a pictograph showing a knife (刂) cutting grain (禾), depicting harvest. From the idea of a sharp blade reaping crops, it extended to mean 'sharp,' then 'benefit,' 'profit,' or 'advantage' — the gain that comes from a successful harvest.