double-digit是个形容词，它的意思是“relating to a number or series of numbers between 10 and 99”，即“两位数的”。

【例句】
The country had 15 years of double-digitinflation.
那个国家有15年通货膨胀率维持在两位数。

The company is still growing at a double-digit pace today.

今天，该公司仍在以两位数的速度增长。