兑 duì convert
cash; check; to exchange; to add
How it came to be
A figure with two strokes rising off the head: breath going out, or a smile opening. The old dictionary reads it as speaking, which is where the speak character comes from.
How it is used
- To exchange/convert, and to make good on something - 兑换 (duìhuàn) to exchange currency, 兑现 (duìxiàn) to cash a check / to honor a promise.
- 兑现 is a favorite metaphor: 兑现承诺 (duìxiàn chéngnuò) to deliver on a promise, as if cashing it in.
- Also 'to dilute/add' in speech - 兑点儿水 (duì diǎnr shuǐ) to add some water.