期货升水，简称升水，又称正差价，是指一种商品的期货价格比合同到期日预期现货价格更高的情况。与之相反的称为期货贴水或逆差价。

升水的英文表达为contango或forwardation，贴水的英文表达为backwardation。

远期汇率与即期汇率的差额用升水、贴水和平价来表示。升水意味着远期汇率比即期的要高，贴水则反之。

具体可看一下各自的英文释义：

Contango is a situation where the futures price of a commodity is higher than the spot price. Contango usually occurs when an asset's price is expected to rise over time. That results in an upward-sloping forward curve.

Forwardation is a term used in pricing futures contracts whereby the futures price of a commodity or currency is trading higher than the spot (cash) price of the commodity for immediate delivery. The term forwardation is more commonly known as contango.

Backwardation is when the current price, or spot price, of an underlying asset is higher than prices trading in the futures market.

参考译文：

Contango是指一种商品的期货价格高于现货价格的情况。Contango通常发生在一个资产的价格预计会随着时间的推移而上升，会呈现一个向上倾斜的远期曲线。

Forwardation是一个用于期货合约定价的术语，即一种商品或货币的期货价格高于该商品立即交割的现货（现金）价格。Forwardation一词更多地被称为contango。

Backwardation是指相关资产的当前价格或现货价格高于期货市场的交易价格。