汇率用英语是表示为 exchange rate。这个词来源于拉丁语，exchange 源自 "ex-" 和 "cambium"，意思是"变更"或"交换"；rate 则源自 "ratio"，意思是"比率"。

例句：

The exchange rate between the US dollar and the euro is currently 1.2.

目前美元与欧元的汇率是 1.2。

The exchange rate fluctuates constantly.

汇率不断波动。

The central bank sets the exchange rate.

中央银行设定汇率。