having three parts of the same type, or happening three times

Her trainer is a triple Olympic champion. 她的教练是3届奥运会冠军。

There's a triple bill of Hitchcock films (= three films) on at the cinema next Sunday. 下周日将有3部希区柯克的影片在这家电影院上映。

three times as large as something

The number of one-parent households reached 10.1 million in 2011, nearly triple that of 1981. 1991年单亲家庭的数量达到了1010万，几乎是1981年的3倍。

to increase three times in size or amount, or to make something do this

We have tripled our output over the past two years. 过去两年里，我们的产量增加了两倍。

The workforce has tripled in size since the new factory opened. 自新工厂开工以来，职工人数已经增加了两倍。